Merge branch 'v2_develop' of tig:tig/Terminal.Gui into v2_develop

.editorconfig

@@ -82,8 +82,8 @@ dotnet_diagnostic.cs0464.severity = warning
 dotnet_diagnostic.cs0465.severity = warning
 dotnet_diagnostic.cs0469.severity = warning
 dotnet_diagnostic.cs0472.severity = warning
-dotnet_diagnostic.cs0612.severity = warning
-dotnet_diagnostic.cs0618.severity = warning
+dotnet_diagnostic.cs0612.severity = none
+dotnet_diagnostic.cs0618.severity = none
 dotnet_diagnostic.cs0628.severity = warning
 dotnet_diagnostic.cs0642.severity = warning
 dotnet_diagnostic.cs0649.severity = warning
@@ -94,7 +94,7 @@ dotnet_diagnostic.cs0659.severity = warning
 dotnet_diagnostic.cs0660.severity = warning
 dotnet_diagnostic.cs0661.severity = warning
 dotnet_diagnostic.cs0665.severity = warning
-dotnet_diagnostic.cs0672.severity = warning
+dotnet_diagnostic.cs0672.severity = none
 dotnet_diagnostic.cs0675.severity = warning
 dotnet_diagnostic.cs0693.severity = warning
 dotnet_diagnostic.cs0728.severity = warning

.github/workflows/build.yml → .github/workflows/build-validation.yml

@@ -1,4 +1,4 @@
-name: Build Solution
+name: Build Validation
 
 on:
   push:
@@ -9,18 +9,11 @@ on:
     branches: [ v2_release, v2_develop ]
     paths-ignore:
       - '**.md'
-  workflow_call:
-    outputs:
-      artifact-name:
-        description: "Name of the build artifacts"
-        value: ${{ jobs.build.outputs.artifact-name }}
       
 jobs:
-  build:
-    name: Build Debug & Release
+  build-validation:
+    name: Build All Configurations
     runs-on: ubuntu-latest
-    outputs:
-      artifact-name: build-artifacts
     
     timeout-minutes: 10
     steps:
@@ -63,14 +56,3 @@ jobs:
 
     - name: Build Release Solution
       run: dotnet build --configuration Release --no-restore -property:NoWarn=0618%3B0612
-
-    - name: Upload build artifacts
-      uses: actions/upload-artifact@v4
-      with:
-        name: build-artifacts
-        path: |
-          **/bin/Debug/**
-          **/obj/Debug/**
-          **/bin/Release/**
-          **/obj/Release/**
-        retention-days: 1

.github/workflows/integration-tests.yml

@@ -1,5 +1,4 @@
 name: Build & Run Integration Tests
-
 on:
   push:
     branches: [ v2_release, v2_develop ]
@@ -9,57 +8,99 @@ on:
     branches: [ v2_release, v2_develop ]
     paths-ignore:
       - '**.md'
-      
+
 jobs:
-  # Call the build workflow to build the solution once
   build:
-    uses: ./.github/workflows/build.yml
+    uses: ./.github/workflows/quick-build.yml
 
   integration_tests:
     name: Integration Tests
     runs-on: ${{ matrix.os }}
     needs: build
     strategy:
-      # Turn off fail-fast to let all runners run even if there are errors
-      fail-fast: true
+      fail-fast: false  # Let all OSes finish even if one fails
       matrix:
         os: [ ubuntu-latest, windows-latest, macos-latest ]
+    timeout-minutes: 15
 
-    timeout-minutes: 10
     steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup .NET Core
+        uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: 8.x
+          dotnet-quality: ga
+
+      - name: Download build artifacts
+        uses: actions/download-artifact@v4
+        with:
+          name: test-build-artifacts
+          path: .
 
-    - name: Checkout code
-      uses: actions/checkout@v4
+      - name: Restore NuGet packages
+        run: dotnet restore
 
-    - name: Setup .NET Core
-      uses: actions/setup-dotnet@v4
-      with:
-        dotnet-version: 8.x
-        dotnet-quality: 'ga'
+      - name: Disable Windows Defender (Windows only)
+        if: runner.os == 'Windows'
+        shell: powershell
+        run: |
+          Add-MpPreference -ExclusionPath "${{ github.workspace }}"
+          Add-MpPreference -ExclusionProcess "dotnet.exe"
+          Add-MpPreference -ExclusionProcess "testhost.exe"
+          Add-MpPreference -ExclusionProcess "VSTest.Console.exe"
 
-    - name: Download build artifacts
-      uses: actions/download-artifact@v4
-      with:
-        name: build-artifacts
-        path: .
+      - name: Set VSTEST_DUMP_PATH
+        shell: bash
+        run: echo "VSTEST_DUMP_PATH=logs/IntegrationTests/${{ runner.os }}/" >> $GITHUB_ENV
 
-    - name: Restore NuGet packages
-      run: dotnet restore
+      - name: Run IntegrationTests
+        shell: bash
+        run: |
+          if [ "${{ runner.os }}" == "Linux" ]; then
+            # Run with coverage on Linux only
+            dotnet test Tests/IntegrationTests \
+              --no-build \
+              --verbosity minimal \
+              --collect:"XPlat Code Coverage" \
+              --settings Tests/IntegrationTests/runsettings.coverage.xml \
+              --diag:logs/IntegrationTests/${{ runner.os }}/logs.txt \
+              --blame \
+              --blame-crash \
+              --blame-hang \
+              --blame-hang-timeout 60s \
+              --blame-crash-collect-always
+          else
+            # Run without coverage on Windows/macOS for speed
+            dotnet test Tests/IntegrationTests \
+              --no-build \
+              --verbosity minimal \
+              --settings Tests/IntegrationTests/runsettings.xml \
+              --diag:logs/IntegrationTests/${{ runner.os }}/logs.txt \
+              --blame \
+              --blame-crash \
+              --blame-hang \
+              --blame-hang-timeout 60s \
+              --blame-crash-collect-always
+          fi
 
-    - name: Set VSTEST_DUMP_PATH
-      shell: bash
-      run: echo "{VSTEST_DUMP_PATH}={logs/${{ runner.os }}/}" >> $GITHUB_ENV
+      - name: Upload Integration Test Logs
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: integration_tests-logs-${{ runner.os }}
+          path: |
+            logs/IntegrationTests/
+            TestResults/
 
-    - name: Run IntegrationTests
-      run: |
-       dotnet test Tests/IntegrationTests --no-build --verbosity normal --diag:logs/${{ runner.os }}/logs.txt --blame --blame-crash --blame-hang --blame-hang-timeout 60s --blame-crash-collect-always -- xunit.stopOnFail=true
-     
-    - name: Upload Test Logs
-      if: always()
-      uses: actions/upload-artifact@v4
-      with:
-        name: integration-test-logs-${{ runner.os }}
-        path: |
-          logs/    
-          TestResults/IntegrationTests/
+      - name: Upload Integration Tests Coverage to Codecov
+        if: matrix.os == 'ubuntu-latest' && always()
+        uses: codecov/codecov-action@v4
+        with:
+          files: TestResults/**/coverage.cobertura.xml
+          flags: integrationtests
+          name: IntegrationTests-${{ runner.os }}
+          token: ${{ secrets.CODECOV_TOKEN }}
+          fail_ci_if_error: false
 

.github/workflows/quick-build.yml

@@ -0,0 +1,43 @@
+name: Quick Build for Tests
+
+on:
+  workflow_call:
+    outputs:
+      artifact-name:
+        description: "Name of the build artifacts"
+        value: ${{ jobs.quick-build.outputs.artifact-name }}
+      
+jobs:
+  quick-build:
+    name: Build Debug Only
+    runs-on: ubuntu-latest
+    outputs:
+      artifact-name: test-build-artifacts
+    
+    timeout-minutes: 5
+    steps:
+
+    - name: Checkout code
+      uses: actions/checkout@v4
+
+    - name: Setup .NET Core
+      uses: actions/setup-dotnet@v4
+      with:
+        dotnet-version: 8.x
+        dotnet-quality: 'ga'
+
+    - name: Restore dependencies
+      run: dotnet restore
+
+    # Suppress CS0618 (member is obsolete) and CS0612 (member is obsolete without message)
+    - name: Build Debug
+      run: dotnet build --configuration Debug --no-restore -property:NoWarn=0618%3B0612
+
+    - name: Upload build artifacts
+      uses: actions/upload-artifact@v4
+      with:
+        name: test-build-artifacts
+        path: |
+          **/bin/Debug/**
+          **/obj/Debug/**
+        retention-days: 1

.github/workflows/unit-tests.yml

@@ -11,9 +11,9 @@ on:
       - '**.md'
       
 jobs:
-  # Call the build workflow to build the solution once
+  # Call the quick-build workflow to build Debug configuration only
   build:
-    uses: ./.github/workflows/build.yml
+    uses: ./.github/workflows/quick-build.yml
 
   non_parallel_unittests:
     name: Non-Parallel Unit Tests  
@@ -21,11 +21,11 @@ jobs:
     needs: build
     strategy:
       # Turn off fail-fast to let all runners run even if there are errors
-      fail-fast: true
+      fail-fast: false
       matrix:
         os: [ ubuntu-latest, windows-latest, macos-latest ]
 
-    timeout-minutes: 10
+    timeout-minutes: 15  # Increased from 10 for Windows
     steps:
 
     - name: Checkout code
@@ -40,26 +40,56 @@ jobs:
     - name: Download build artifacts
       uses: actions/download-artifact@v4
       with:
-        name: build-artifacts
+        name: test-build-artifacts
         path: .
 
+    # KEEP THIS - It's needed for --no-build to work
     - name: Restore NuGet packages
       run: dotnet restore
 
-# Test
-    # Note: The --blame and VSTEST_DUMP_PATH stuff is needed to diagnose the test runner crashing on ubuntu/mac
-    # See https://github.com/microsoft/vstest/issues/2952 for why the --blame stuff below is needed.
-    # Without it, the test runner crashes on ubuntu (but not Windows or mac)
+    # Optimize Windows performance
+    - name: Disable Windows Defender (Windows only)
+      if: runner.os == 'Windows'
+      shell: powershell
+      run: |
+        Add-MpPreference -ExclusionPath "${{ github.workspace }}"
+        Add-MpPreference -ExclusionProcess "dotnet.exe"
+        Add-MpPreference -ExclusionProcess "testhost.exe"
+        Add-MpPreference -ExclusionProcess "VSTest.Console.exe"
 
     - name: Set VSTEST_DUMP_PATH
       shell: bash
-      run: echo "{VSTEST_DUMP_PATH}={logs/UnitTests/${{ runner.os }}/}" >> $GITHUB_ENV
+      run: echo "VSTEST_DUMP_PATH=logs/UnitTests/${{ runner.os }}/" >> $GITHUB_ENV
 
     - name: Run UnitTests
+      shell: bash
       run: |
-       dotnet test Tests/UnitTests --no-build --verbosity normal --collect:"XPlat Code Coverage" --settings Tests/UnitTests/coverlet.runsettings --diag:logs/UnitTests/${{ runner.os }}/logs.txt --blame --blame-crash --blame-hang --blame-hang-timeout 60s --blame-crash-collect-always -- xunit.stopOnFail=false
-     
-       # mv -v Tests/UnitTests/TestResults/*/*.* TestResults/UnitTests/
+        if [ "${{ runner.os }}" == "Linux" ]; then
+          # Run with coverage on Linux only
+          dotnet test Tests/UnitTests \
+            --no-build \
+            --verbosity normal \
+            --collect:"XPlat Code Coverage" \
+            --settings Tests/UnitTests/runsettings.xml \
+            --diag:logs/UnitTests/${{ runner.os }}/logs.txt \
+            --blame \
+            --blame-crash \
+            --blame-hang \
+            --blame-hang-timeout 60s \
+            --blame-crash-collect-always
+        else
+          # Run without coverage on Windows/macOS for speed
+          dotnet test Tests/UnitTests \
+            --no-build \
+            --verbosity normal \
+            --settings Tests/UnitTests/runsettings.xml \
+            --diag:logs/UnitTests/${{ runner.os }}/logs.txt \
+            --blame \
+            --blame-crash \
+            --blame-hang \
+            --blame-hang-timeout 120s \
+            --blame-crash-collect-always
+        fi
 
     - name: Upload Test Logs
       if: always()
@@ -68,19 +98,29 @@ jobs:
         name: non_parallel_unittests-logs-${{ runner.os }}
         path: |
           logs/UnitTests    
-          TestResults/UnitTests/
+          TestResults/
   
+    - name: Upload Non-Parallel UnitTests Coverage to Codecov
+      if: matrix.os == 'ubuntu-latest' && always()
+      uses: codecov/codecov-action@v4
+      with:
+        files: TestResults/**/coverage.cobertura.xml
+        flags: unittests-nonparallel
+        name: UnitTests-${{ runner.os }}
+        token: ${{ secrets.CODECOV_TOKEN }}
+        fail_ci_if_error: false
+
   parallel_unittests:
     name: Parallel Unit Tests  
     runs-on: ${{ matrix.os }}
     needs: build
     strategy:
       # Turn off fail-fast to let all runners run even if there are errors
-      fail-fast: true
+      fail-fast: false
       matrix:
         os: [ ubuntu-latest, windows-latest, macos-latest ]
 
-    timeout-minutes: 10
+    timeout-minutes: 15
     steps:
 
     - name: Checkout code
@@ -95,26 +135,54 @@ jobs:
     - name: Download build artifacts
       uses: actions/download-artifact@v4
       with:
-        name: build-artifacts
+        name: test-build-artifacts
         path: .
 
     - name: Restore NuGet packages
       run: dotnet restore
 
-# Test
-    # Note: The --blame and VSTEST_DUMP_PATH stuff is needed to diagnose the test runner crashing on ubuntu/mac
-    # See https://github.com/microsoft/vstest/issues/2952 for why the --blame stuff below is needed.
-    # Without it, the test runner crashes on ubuntu (but not Windows or mac)
+    - name: Disable Windows Defender (Windows only)
+      if: runner.os == 'Windows'
+      shell: powershell
+      run: |
+        Add-MpPreference -ExclusionPath "${{ github.workspace }}"
+        Add-MpPreference -ExclusionProcess "dotnet.exe"
+        Add-MpPreference -ExclusionProcess "testhost.exe"
+        Add-MpPreference -ExclusionProcess "VSTest.Console.exe"
 
     - name: Set VSTEST_DUMP_PATH
       shell: bash
-      run: echo "{VSTEST_DUMP_PATH}={logs/UnitTestsParallelizable/${{ runner.os }}/}" >> $GITHUB_ENV
+      run: echo "VSTEST_DUMP_PATH=logs/UnitTestsParallelizable/${{ runner.os }}/" >> $GITHUB_ENV
 
     - name: Run UnitTestsParallelizable
+      shell: bash
       run: |
-       dotnet test Tests/UnitTestsParallelizable --no-build --verbosity normal --collect:"XPlat Code Coverage" --settings Tests/UnitTestsParallelizable/coverlet.runsettings --diag:logs/UnitTestsParallelizable/${{ runner.os }}/logs.txt --blame --blame-crash --blame-hang --blame-hang-timeout 60s --blame-crash-collect-always -- xunit.stopOnFail=false
-     
-       # mv -v Tests/UnitTestsParallelizable/TestResults/*/*.* TestResults/UnitTestsParallelizable/
+        if [ "${{ runner.os }}" == "Linux" ]; then
+          # Run with coverage on Linux only
+          dotnet test Tests/UnitTestsParallelizable \
+            --no-build \
+            --verbosity normal \
+            --collect:"XPlat Code Coverage" \
+            --settings Tests/UnitTests/runsettings.coverage.xml \
+            --diag:logs/UnitTestsParallelizable/${{ runner.os }}/logs.txt \
+            --blame \
+            --blame-crash \
+            --blame-hang \
+            --blame-hang-timeout 60s \
+            --blame-crash-collect-always
+        else
+          # Run without coverage on Windows/macOS for speed
+          dotnet test Tests/UnitTestsParallelizable \
+            --no-build \
+            --verbosity normal \
+            --settings Tests/UnitTestsParallelizable/runsettings.xml \
+            --diag:logs/UnitTestsParallelizable/${{ runner.os }}/logs.txt \
+            --blame \
+            --blame-crash \
+            --blame-hang \
+            --blame-hang-timeout 60s \
+            --blame-crash-collect-always
+        fi
 
     - name: Upload UnitTestsParallelizable Logs
       if: always()
@@ -123,4 +191,14 @@ jobs:
         name: parallel_unittests-logs-${{ runner.os }}
         path: |
           logs/UnitTestsParallelizable/
-          TestResults/UnitTestsParallelizable/
+          TestResults/
+  
+    - name: Upload Parallelizable UnitTests Coverage to Codecov
+      if: matrix.os == 'ubuntu-latest' && always()
+      uses: codecov/codecov-action@v4
+      with:
+        files: TestResults/**/coverage.cobertura.xml
+        flags: unittests-parallel
+        name: UnitTestsParallelizable-${{ runner.os }}
+        token: ${{ secrets.CODECOV_TOKEN }}
+        fail_ci_if_error: false

.gitignore

@@ -68,3 +68,8 @@ BenchmarkDotNet.Artifacts/
 *.log.*
 
 log.*
+
+/Tests/coverage/
+!/Tests/coverage/.gitkeep   # keep folder in repo
+/Tests/report/
+*.cobertura.xml

CONTRIBUTING.md

@@ -23,11 +23,10 @@ Welcome! This guide provides everything you need to know to contribute effective
 
 ## Project Overview
 
-**Terminal.Gui** is a cross-platform UI toolkit for creating console-based graphical user interfaces in .NET. It's a large codebase (~1,050 C# files, 333MB) providing a comprehensive framework for building interactive console applications with support for keyboard and mouse input, customizable views, and a robust event system.
+**Terminal.Gui** is a cross-platform UI toolkit for creating console-based graphical user interfaces in .NET. It's a large codebase (~1,050 C# files) providing a comprehensive framework for building interactive console applications with support for keyboard and mouse input, customizable views, and a robust event system.
 
 **Key characteristics:**
 - **Language**: C# (net8.0)
-- **Size**: ~496 source files in core library, ~1,050 total C# files
 - **Platform**: Cross-platform (Windows, macOS, Linux)
 - **Architecture**: Console UI toolkit with driver-based architecture
 - **Version**: v2 (Alpha), v1 (maintenance mode)
@@ -88,25 +87,12 @@ Welcome! This guide provides everything you need to know to contribute effective
    dotnet test Tests/IntegrationTests --no-build --verbosity normal
    ```
 
-**Important**: Tests may take significant time. CI uses blame flags for crash detection:
-```bash
---diag:logs/UnitTests/logs.txt --blame --blame-crash --blame-hang --blame-hang-timeout 60s --blame-crash-collect-always
-```
-
 ### Common Build Issues
 
 #### Issue: Build Warnings
-- **Expected**: ~326 warnings (nullable refs, unused vars, xUnit suggestions)
+- **Expected**: None warnings (~100 currently).
 - **Action**: Don't add new warnings; fix warnings in code you modify
 
-#### Issue: Test Timeouts
-- **Expected**: Tests can take 5-10 minutes
-- **Action**: Use appropriate timeout values (60-120 seconds for test commands)
-
-#### Issue: Restore Failures
-- **Solution**: Ensure `dotnet restore` completes before building
-- **Note**: Takes 15-20 seconds on first run
-
 #### Issue: NativeAot/SelfContained Build
 - **Solution**: Restore these projects explicitly:
   ```bash
@@ -135,19 +121,18 @@ dotnet run --project Examples/UICatalog/UICatalog.csproj
 
 ### Code Formatting
 
+**⚠️ CRITICAL - These rules MUST be followed in ALL new or modified code:**
+
 - **Do NOT add formatting tools** - Use existing `.editorconfig` and `Terminal.sln.DotSettings`
 - Format code with:
   1. ReSharper/Rider (`Ctrl-E-C`)
   2. JetBrains CleanupCode CLI tool (free)
   3. Visual Studio (`Ctrl-K-D`) as fallback
 - **Only format files you modify**
-
-### Critical Coding Rules
-
-**⚠️ CRITICAL - These rules MUST be followed in ALL new or modified code:**
-
-#### Type Declarations and Object Creation
-
+- Follow `.editorconfig` settings (e.g., braces on new lines, spaces after keywords)
+- 4-space indentation
+- No trailing whitespace
+- File-scoped namespaces
 - **ALWAYS use explicit types** - Never use `var` except for built-in simple types (`int`, `string`, `bool`, `double`, `float`, `decimal`, `char`, `byte`)
   ```csharp
   // ✅ CORRECT - Explicit types
@@ -163,7 +148,7 @@ dotnet run --project Examples/UICatalog/UICatalog.csproj
   var views = new List<View?>();
   ```
 
-- **ALWAYS use target-typed `new()`** - Use `new ()` instead of `new TypeName()` when the type is already declared
+- **ALWAYS use target-typed `new ()`** - Use `new ()` instead of `new TypeName()` when the type is already declared
   ```csharp
   // ✅ CORRECT - Target-typed new
   View view = new () { Width = 10 };
@@ -174,13 +159,6 @@ dotnet run --project Examples/UICatalog/UICatalog.csproj
   MouseEventArgs args = new MouseEventArgs();
   ```
 
-#### Other Conventions
-
-- Follow `.editorconfig` settings (e.g., braces on new lines, spaces after keywords)
-- 4-space indentation
-- No trailing whitespace
-- File-scoped namespaces
-
 **⚠️ CRITICAL - These conventions apply to ALL code - production code, test code, examples, and samples.**
 
 ---
@@ -191,6 +169,11 @@ dotnet run --project Examples/UICatalog/UICatalog.csproj
 
 - **Never decrease code coverage** - PRs must maintain or increase coverage
 - Target: 70%+ coverage for new code
+- **Coverage collection**:
+- Centralized in `TestResults/` directory at repository root
+- Collected only on Linux (ubuntu-latest) runners in CI for performance
+- Windows and macOS runners skip coverage collection to reduce execution time
+- Coverage reports uploaded to Codecov automatically from Linux runner
 - CI monitors coverage on each PR
 
 ### Test Patterns
@@ -258,33 +241,58 @@ The repository uses multiple GitHub Actions workflows. What runs and when:
 - **Triggers**: push and pull_request to `v2_release`, `v2_develop` (ignores `**.md`); supports `workflow_call`
 - **Runner/timeout**: `ubuntu-latest`, 10 minutes
 - **Steps**:
-  - Checkout and setup .NET 8.x GA
-  - `dotnet restore`
-  - Build Debug: `dotnet build --configuration Debug --no-restore -property:NoWarn=0618%3B0612`
-  - Build Release (library): `dotnet build Terminal.Gui/Terminal.Gui.csproj --configuration Release --no-incremental --force -property:NoWarn=0618%3B0612`
-  - Pack Release: `dotnet pack Terminal.Gui/Terminal.Gui.csproj --configuration Release --output ./local_packages -property:NoWarn=0618%3B0612`
-  - Restore NativeAot/SelfContained examples, then restore solution again
-  - Build Release for `Examples/NativeAot` and `Examples/SelfContained`
-  - Build Release solution
-  - Upload artifacts named `build-artifacts`, retention 1 day
+- Checkout and setup .NET 8.x GA
+- `dotnet restore`
+- Build Debug: `dotnet build --configuration Debug --no-restore -property:NoWarn=0618%3B0612`
+- Build Release (library): `dotnet build Terminal.Gui/Terminal.Gui.csproj --configuration Release --no-incremental --force -property:NoWarn=0618%3B0612`
+- Pack Release: `dotnet pack Terminal.Gui/Terminal.Gui.csproj --configuration Release --output ./local_packages -property:NoWarn=0618%3B0612`
+- Restore NativeAot/SelfContained examples, then restore solution again
+- Build Release for `Examples/NativeAot` and `Examples/SelfContained`
+- Build Release solution
+- Upload artifacts named `build-artifacts`, retention 1 day
 
 ### 2) Build & Run Unit Tests (`.github/workflows/unit-tests.yml`)
 
 - **Triggers**: push and pull_request to `v2_release`, `v2_develop` (ignores `**.md`)
-- **Process**: Calls build workflow, then runs:
-  - Non-parallel UnitTests on Ubuntu/Windows/macOS matrix with coverage and blame/diag flags; `xunit.stopOnFail=false`
-  - Parallel UnitTestsParallelizable similarly with coverage; `xunit.stopOnFail=false`
-  - Uploads logs per-OS
+- **Matrix**: Ubuntu/Windows/macOS
+- **Timeout**: 15 minutes per job
+- **Process**:
+1. Calls build workflow to build solution once
+2. Downloads build artifacts
+3. Runs `dotnet restore` (required for `--no-build` to work)
+4. **Performance optimizations**:
+   - Disables Windows Defender on Windows runners (significant speedup)
+   - Collects code coverage **only on Linux** (ubuntu-latest) for performance
+   - Windows and macOS skip coverage collection to reduce test time
+   - Increased blame-hang-timeout to 120s for Windows/macOS (60s for Linux)
+5. Runs two test jobs:
+   - **Non-parallel UnitTests**: `Tests/UnitTests` with blame/diag flags; `xunit.stopOnFail=false`
+   - **Parallel UnitTestsParallelizable**: `Tests/UnitTestsParallelizable` with blame/diag flags; `xunit.stopOnFail=false`
+6. Uploads test logs and diagnostic data from all runners
+7. **Uploads code coverage to Codecov only from Linux runner**
+
+**Test results**: All tests output to unified `TestResults/` directory at repository root
 
 ### 3) Build & Run Integration Tests (`.github/workflows/integration-tests.yml`)
 
 - **Triggers**: push and pull_request to `v2_release`, `v2_develop` (ignores `**.md`)
-- **Process**: Calls build workflow, then runs IntegrationTests on matrix with blame/diag; `xunit.stopOnFail=true`
-- Uploads logs per-OS
+- **Matrix**: Ubuntu/Windows/macOS
+- **Timeout**: 15 minutes
+- **Process**:
+1. Calls build workflow
+2. Downloads build artifacts
+3. Runs `dotnet restore`
+4. **Performance optimizations** (same as unit tests):
+   - Disables Windows Defender on Windows runners
+   - Collects code coverage **only on Linux**
+   - Increased blame-hang-timeout to 120s for Windows/macOS
+5. Runs IntegrationTests with blame/diag flags; `xunit.stopOnFail=true`
+6. Uploads logs per-OS
+7. **Uploads coverage to Codecov only from Linux runner**
 
 ### 4) Publish to NuGet (`.github/workflows/publish.yml`)
 
-- **Triggers**: push to `v2_release`, `v2_develop`, and tags `v*` (ignores `**.md`)
+- **Triggers**: push to `v2_release`, `v2_develop`, and tags `v*`(ignores `**.md`)
 - Uses GitVersion to compute SemVer, builds Release, packs with symbols, and pushes to NuGet.org using `NUGET_API_KEY`
 
 ### 5) Build and publish API docs (`.github/workflows/api-docs.yml`)
@@ -292,6 +300,7 @@ The repository uses multiple GitHub Actions workflows. What runs and when:
 - **Triggers**: push to `v1_release` and `v2_develop`
 - Builds DocFX site on Windows and deploys to GitHub Pages when `ref_name` is `v2_release` or `v2_develop`
 
+
 ### Replicating CI Locally
 
 ```bash
@@ -323,9 +332,9 @@ dotnet build --configuration Release --no-restore
 ### Main Directories
 
 **`/Terminal.Gui/`** - Core library (496 C# files):
-- `App/` - Application lifecycle (`Application.cs` static class, `RunState`, `MainLoop`)
+- `App/` - Application lifecycle (`Application.cs` static class, `SessionToken`, `MainLoop`)
 - `Configuration/` - `ConfigurationManager` for settings
-- `Drivers/` - Console driver implementations (`IConsoleDriver`, `NetDriver`, `UnixDriver`, `WindowsDriver`)
+- `Drivers/` - Console driver implementations (`Dotnet`, `Windows`, `Unix`, `Fake`)
 - `Drawing/` - Rendering system (attributes, colors, glyphs)
 - `Input/` - Keyboard and mouse input handling
 - `ViewBase/` - Core `View` class hierarchy and layout

Examples/NativeAot/Program.cs

@@ -12,8 +12,8 @@ namespace NativeAot;
 
 public static class Program
 {
-    [RequiresUnreferencedCode ("Calls Terminal.Gui.Application.Init(IConsoleDriver, String)")]
-    [RequiresDynamicCode ("Calls Terminal.Gui.Application.Init(IConsoleDriver, String)")]
+    [RequiresUnreferencedCode ("Calls Terminal.Gui.Application.Init(IDriver, String)")]
+    [RequiresDynamicCode ("Calls Terminal.Gui.Application.Init(IDriver, String)")]
     private static void Main (string [] args)
     {
         ConfigurationManager.Enable(ConfigLocations.All);

Examples/SelfContained/Program.cs

@@ -12,7 +12,7 @@ namespace SelfContained;
 
 public static class Program
 {
-    [RequiresUnreferencedCode ("Calls Terminal.Gui.Application.Run<T>(Func<Exception, Boolean>, IConsoleDriver)")]
+    [RequiresUnreferencedCode ("Calls Terminal.Gui.Application.Run<T>(Func<Exception, Boolean>, IDriver)")]
     private static void Main (string [] args)
     {
         ConfigurationManager.Enable (ConfigLocations.All);

Examples/UICatalog/Scenario.cs

@@ -189,32 +189,25 @@ public class Scenario : IDisposable
             }
 
             Application.Iteration += OnApplicationOnIteration;
-            Application.Driver!.ClearedContents += (sender, args) => BenchmarkResults.ClearedContentCount++;
 
-            if (Application.Driver is ConsoleDriver cd)
-            {
-                cd.Refreshed += (sender, args) =>
-                                                 {
-                                                     BenchmarkResults.RefreshedCount++;
-                                                     if (args.Value)
-                                                     {
-                                                         BenchmarkResults.UpdatedCount++;
-                                                     }
-                                                 };
-
-            }
-            Application.NotifyNewRunState += OnApplicationNotifyNewRunState;
+            Application.Driver!.ClearedContents += OnClearedContents;
+            Application.SessionBegun += OnApplicationSessionBegun;
 
 
             _stopwatch = Stopwatch.StartNew ();
         }
         else
         {
-            Application.NotifyNewRunState -= OnApplicationNotifyNewRunState;
+            Application.Driver!.ClearedContents -= OnClearedContents;
+            Application.SessionBegun -= OnApplicationSessionBegun;
             Application.Iteration -= OnApplicationOnIteration;
             BenchmarkResults.Duration = _stopwatch!.Elapsed;
             _stopwatch?.Stop ();
         }
+
+        return;
+
+        void OnClearedContents (object? sender, EventArgs args) => BenchmarkResults.ClearedContentCount++;
     }
 
     private void OnApplicationOnIteration (object? s, IterationEventArgs a)
@@ -226,7 +219,7 @@ public class Scenario : IDisposable
         }
     }
 
-    private void OnApplicationNotifyNewRunState (object? sender, RunStateEventArgs e)
+    private void OnApplicationSessionBegun (object? sender, SessionTokenEventArgs e)
     {
         SubscribeAllSubViews (Application.Top!);
 

Examples/UICatalog/Scenarios/Adornments.cs

@@ -26,7 +26,7 @@ public class Adornments : Scenario
             X = Pos.AnchorEnd ()
         };
 
-        editor.Border.Thickness = new (1, 2, 1, 1);
+        editor.Border!.Thickness = new (1, 2, 1, 1);
 
         app.Add (editor);
 
@@ -71,7 +71,7 @@ public class Adornments : Scenario
             Width = 40,
             Height = 6 // TODO: Use Dim.Auto
         };
-        label.Border.Thickness = new (1, 3, 1, 1);
+        label.Border!.Thickness = new (1, 3, 1, 1);
 
         var btnButtonInWindow = new Button { X = Pos.AnchorEnd (), Y = Pos.AnchorEnd (), Text = "Button" };
 
@@ -84,13 +84,13 @@ public class Adornments : Scenario
             SchemeName = "Dialog"
         };
 
-        window.Margin.Data = "Margin";
-        window.Margin.Text = "Margin Text";
-        window.Margin.Thickness = new (0);
+        window.Margin!.Data = "Margin";
+        window.Margin!.Text = "Margin Text";
+        window.Margin!.Thickness = new (0);
 
-        window.Border.Data = "Border";
-        window.Border.Text = "Border Text";
-        window.Border.Thickness = new (0);
+        window.Border!.Data = "Border";
+        window.Border!.Text = "Border Text";
+        window.Border!.Thickness = new (0);
 
         window.Padding.Data = "Padding";
         window.Padding.Text = "Padding Text line 1\nPadding Text line 3\nPadding Text line 3\nPadding Text line 4\nPadding Text line 5";
@@ -134,14 +134,14 @@ public class Adornments : Scenario
                                   };
                                   btnButtonInPadding.Accepting += (s, e) => MessageBox.Query (20, 7, "Hi", "Button in Padding Pressed!", "Ok");
                                   btnButtonInPadding.BorderStyle = LineStyle.Dashed;
-                                  btnButtonInPadding.Border.Thickness = new (1, 1, 1, 1);
+                                  btnButtonInPadding.Border!.Thickness = new (1, 1, 1, 1);
                                   window.Padding.Add (btnButtonInPadding);
 
 #if SUBVIEW_BASED_BORDER
-                                btnButtonInPadding.Border.CloseButton.Visible = true;
+                                btnButtonInPadding.Border!.CloseButton.Visible = true;
 
-                                view.Border.CloseButton.Visible = true;
-                                view.Border.CloseButton.Accept += (s, e) =>
+                                view.Border!.CloseButton.Visible = true;
+                                view.Border!.CloseButton.Accept += (s, e) =>
                                                                   {
                                                                       MessageBox.Query (20, 7, "Hi", "Window Close Button Pressed!", "Ok");
                                                                       e.Handled = true;

Examples/UICatalog/Scenarios/AllViewsTester.cs

@@ -38,7 +38,7 @@ public class AllViewsTester : Scenario
 
         // Set the BorderStyle we use for all subviews, but disable the app border thickness
         app.Border!.LineStyle = LineStyle.Heavy;
-        app.Border.Thickness = new (0);
+        app.Border!.Thickness = new (0);
 
 
         _viewClasses = GetAllViewClassesCollection ()
@@ -158,16 +158,13 @@ public class AllViewsTester : Scenario
 
         _eventLog = new ()
         {
-            // X = Pos.Right(_layoutEditor),
+            X = Pos.AnchorEnd () - 1,
+            Y = 0,
+            Width = 30,
+            Height = Dim.Fill (),
             SuperViewRendersLineCanvas = true
         };
         _eventLog.Border!.Thickness = new (1);
-        _eventLog.X = Pos.AnchorEnd () - 1;
-        _eventLog.Y = 0;
-
-        _eventLog.Height = Dim.Height (_classListView);
-
-        //_eventLog.Width = 30;
 
         _layoutEditor.Width = Dim.Fill (
                                         Dim.Func (
@@ -194,7 +191,6 @@ public class AllViewsTester : Scenario
             Height = Dim.Fill (),
             CanFocus = true,
             TabStop = TabBehavior.TabStop,
-            //SchemeName = SchemeManager.SchemesToSchemeName (Schemes.Base),
             Arrangement = ViewArrangement.LeftResizable | ViewArrangement.BottomResizable | ViewArrangement.RightResizable,
             BorderStyle = LineStyle.Double,
             SuperViewRendersLineCanvas = true
@@ -228,7 +224,7 @@ public class AllViewsTester : Scenario
         if (type.IsGenericType)
         {
             // For each of the <T> arguments
-            List<Type> typeArguments = new ();
+            List<Type> typeArguments = [];
 
             // use <object> or the original type if applicable
             foreach (Type arg in type.GetGenericArguments ())

Examples/UICatalog/Scenarios/AnsiRequestsScenario.cs

@@ -112,7 +112,7 @@ public sealed class AnsiEscapeSequenceRequests : Scenario
 
                                                       break;
                                                   case "CSI_ReportTerminalSizeInChars":
-                                                      selAnsiEscapeSequenceRequest = EscSeqUtils.CSI_ReportTerminalSizeInChars;
+                                                      selAnsiEscapeSequenceRequest = EscSeqUtils.CSI_ReportWindowSizeInChars;
 
                                                       break;
                                                   case "CSI_RequestCursorPositionReport":

Examples/UICatalog/Scenarios/Bars.cs

@@ -40,7 +40,7 @@ public class Bars : Scenario
             SchemeName = "Toplevel",
             Source = new ListWrapper<string> (eventSource)
         };
-        eventLog.Border.Thickness = new (0, 1, 0, 0);
+        eventLog.Border!.Thickness = new (0, 1, 0, 0);
         Application.Top.Add (eventLog);
 
         FrameView menuBarLikeExamples = new ()
@@ -185,9 +185,9 @@ public class Bars : Scenario
 
         menuLikeExamples.Add (popOverMenu);
 
-        menuLikeExamples.MouseClick += MenuLikeExamplesMouseClick;
+        menuLikeExamples.MouseEvent += MenuLikeExamplesMouseEvent;
 
-        void MenuLikeExamplesMouseClick (object sender, MouseEventArgs e)
+        void MenuLikeExamplesMouseEvent (object _, MouseEventArgs e)
         {
             if (e.Flags.HasFlag (MouseFlags.Button3Clicked))
             {

Examples/UICatalog/Scenarios/Buttons.cs

@@ -243,17 +243,17 @@ public class Buttons : Scenario
         };
         main.Add (label);
 
-        var radioGroup = new RadioGroup
+        OptionSelector<Alignment> osAlignment = new ()
         {
             X = 4,
             Y = Pos.Bottom (label) + 1,
-            SelectedItem = 2,
-            RadioLabels = new [] { "_Start", "_End", "_Center", "_Fill" },
-            Title = "_9 RadioGroup",
+            Value = Alignment.Center,
+            AssignHotKeys = true,
+            Title = "_9 OptionSelector",
             BorderStyle = LineStyle.Dotted,
             // CanFocus = false
         };
-        main.Add (radioGroup);
+        main.Add (osAlignment);
 
         // Demo changing hotkey
         string MoveHotkey (string txt)
@@ -292,7 +292,7 @@ public class Buttons : Scenario
         var moveHotKeyBtn = new Button
         {
             X = 2,
-            Y = Pos.Bottom (radioGroup) + 1,
+            Y = Pos.Bottom (osAlignment) + 1,
             Width = Dim.Width (computedFrame) - 2,
             SchemeName = "TopLevel",
             Text = mhkb
@@ -309,7 +309,7 @@ public class Buttons : Scenario
         var moveUnicodeHotKeyBtn = new Button
         {
             X = Pos.Left (absoluteFrame) + 1,
-            Y = Pos.Bottom (radioGroup) + 1,
+            Y = Pos.Bottom (osAlignment) + 1,
             Width = Dim.Width (absoluteFrame) - 2,
             SchemeName = "TopLevel",
             Text = muhkb
@@ -321,48 +321,21 @@ public class Buttons : Scenario
                                        };
         main.Add (moveUnicodeHotKeyBtn);
 
-        radioGroup.SelectedItemChanged += (s, args) =>
-                                          {
-                                              switch (args.SelectedItem)
-                                              {
-                                                  case 0:
-                                                      moveBtn.TextAlignment = Alignment.Start;
-                                                      sizeBtn.TextAlignment = Alignment.Start;
-                                                      moveBtnA.TextAlignment = Alignment.Start;
-                                                      sizeBtnA.TextAlignment = Alignment.Start;
-                                                      moveHotKeyBtn.TextAlignment = Alignment.Start;
-                                                      moveUnicodeHotKeyBtn.TextAlignment = Alignment.Start;
-
-                                                      break;
-                                                  case 1:
-                                                      moveBtn.TextAlignment = Alignment.End;
-                                                      sizeBtn.TextAlignment = Alignment.End;
-                                                      moveBtnA.TextAlignment = Alignment.End;
-                                                      sizeBtnA.TextAlignment = Alignment.End;
-                                                      moveHotKeyBtn.TextAlignment = Alignment.End;
-                                                      moveUnicodeHotKeyBtn.TextAlignment = Alignment.End;
-
-                                                      break;
-                                                  case 2:
-                                                      moveBtn.TextAlignment = Alignment.Center;
-                                                      sizeBtn.TextAlignment = Alignment.Center;
-                                                      moveBtnA.TextAlignment = Alignment.Center;
-                                                      sizeBtnA.TextAlignment = Alignment.Center;
-                                                      moveHotKeyBtn.TextAlignment = Alignment.Center;
-                                                      moveUnicodeHotKeyBtn.TextAlignment = Alignment.Center;
-
-                                                      break;
-                                                  case 3:
-                                                      moveBtn.TextAlignment = Alignment.Fill;
-                                                      sizeBtn.TextAlignment = Alignment.Fill;
-                                                      moveBtnA.TextAlignment = Alignment.Fill;
-                                                      sizeBtnA.TextAlignment = Alignment.Fill;
-                                                      moveHotKeyBtn.TextAlignment = Alignment.Fill;
-                                                      moveUnicodeHotKeyBtn.TextAlignment = Alignment.Fill;
-
-                                                      break;
-                                              }
-                                          };
+        osAlignment.ValueChanged += (s, args) =>
+                                    {
+                                        if (args.Value is null)
+                                        {
+                                            return;
+                                        }
+
+                                        Alignment newValue = args.Value.Value;
+                                        moveBtn.TextAlignment = newValue;
+                                        sizeBtn.TextAlignment = newValue;
+                                        moveBtnA.TextAlignment = newValue;
+                                        sizeBtnA.TextAlignment = newValue;
+                                        moveHotKeyBtn.TextAlignment = newValue;
+                                        moveUnicodeHotKeyBtn.TextAlignment = newValue;
+                                    };
 
         label = new ()
         {

Examples/UICatalog/Scenarios/CharacterMap/CharacterMap.cs

@@ -85,7 +85,7 @@ public class CharacterMap : Scenario
             X = Pos.Right (jumpLabel) + 1,
             Y = Pos.Y (_charMap),
             Width = 17,
-            Caption = "e.g. 01BE3 or ✈"
+            Title = "e.g. 01BE3 or ✈"
 
             //SchemeName = "Dialog"
         };
@@ -365,40 +365,16 @@ public class CharacterMap : Scenario
         options [0] = "All";
         Array.Copy (allCategoryNames, 0, options, 1, allCategoryNames.Length);
 
-        // TODO: When #4126 is merged update this to use OptionSelector<UnicodeCategory?>
-        var selector = new OptionSelector
-        {
-            AssignHotKeysToCheckBoxes = true,
-            Options = options
-        };
+        // TODO: Add a "None" option
+        OptionSelector<UnicodeCategory> selector = new ();
 
         _unicodeCategorySelector = selector;
 
-        // Default to "All"
-        selector.SelectedItem = 0;
+        selector.Value = null;
         _charMap!.ShowUnicodeCategory = null;
 
-        selector.SelectedItemChanged += (s, e) =>
-                                        {
-                                            int? idx = selector.SelectedItem;
-
-                                            if (idx is null)
-                                            {
-                                                return;
-                                            }
-
-                                            if (idx.Value == 0)
-                                            {
-                                                _charMap.ShowUnicodeCategory = null;
-                                            }
-                                            else
-                                            {
-                                                // Map index to UnicodeCategory (offset by 1 because 0 is "All")
-                                                UnicodeCategory cat = Enum.GetValues<UnicodeCategory> () [idx.Value - 1];
-                                                _charMap.ShowUnicodeCategory = cat;
-                                            }
-                                        };
-
-        return new() { CommandView = selector };
+        selector.ValueChanged += (_, e) => _charMap.ShowUnicodeCategory = e.Value;
+
+        return new () { CommandView = selector };
     }
 }

Examples/UICatalog/Scenarios/Clipping.cs

@@ -151,7 +151,7 @@ public class Clipping : Scenario
         //tiled.Padding.Thickness = new (1);
         //tiled.Padding.Diagnostics =  ViewDiagnosticFlags.Thickness;
 
-        //tiled.Margin.Thickness = new (1);
+        //tiled.Margin!.Thickness = new (1);
 
         FrameView fv = new ()
         {

Examples/UICatalog/Scenarios/ColorPicker.cs

@@ -125,26 +125,25 @@ public class ColorPickers : Scenario
         app.Add (_demoView);
 
 
-        // Radio for switching color models
-        var rgColorModel = new RadioGroup ()
+        var osColorModel = new OptionSelector ()
         {
             Y = Pos.Bottom (_demoView),
             Width = Dim.Auto (),
             Height = Dim.Auto (),
-            RadioLabels = new []
-            {
+            Labels =
+            [
                 "_RGB",
                 "_HSV",
                 "H_SL",
                 "_16 Colors"
-            },
-            SelectedItem = (int)foregroundColorPicker.Style.ColorModel,
+            ],
+            Value = (int)foregroundColorPicker.Style.ColorModel,
         };
 
-        rgColorModel.SelectedItemChanged += (_, e) =>
+        osColorModel.ValueChanged += (_, e) =>
                                             {
                                                 // 16 colors
-                                                if (e.SelectedItem == 3)
+                                                if (e.Value == 3)
                                                 {
 
                                                     foregroundColorPicker16.Visible = true;
@@ -161,12 +160,17 @@ public class ColorPickers : Scenario
                                                 {
                                                     foregroundColorPicker16.Visible = false;
                                                     foregroundColorPicker.Visible = true;
-                                                    foregroundColorPicker.Style.ColorModel = (ColorModel)e.SelectedItem;
-                                                    foregroundColorPicker.ApplyStyleChanges ();
 
-                                                    backgroundColorPicker16.Visible = false;
-                                                    backgroundColorPicker.Visible = true;
-                                                    backgroundColorPicker.Style.ColorModel = (ColorModel)e.SelectedItem;
+                                                    if (e.Value is { })
+                                                    {
+                                                        foregroundColorPicker.Style.ColorModel = (ColorModel)e.Value;
+                                                        foregroundColorPicker.ApplyStyleChanges ();
+
+                                                        backgroundColorPicker16.Visible = false;
+                                                        backgroundColorPicker.Visible = true;
+                                                        backgroundColorPicker.Style.ColorModel = (ColorModel)e.Value;
+                                                    }
+
                                                     backgroundColorPicker.ApplyStyleChanges ();
 
 
@@ -176,13 +180,13 @@ public class ColorPickers : Scenario
                                                 }
                                             };
 
-        app.Add (rgColorModel);
+        app.Add (osColorModel);
 
         // Checkbox for switching show text fields on and off
         var cbShowTextFields = new CheckBox ()
         {
             Text = "Show _Text Fields",
-            Y = Pos.Bottom (rgColorModel) + 1,
+            Y = Pos.Bottom (osColorModel) + 1,
             Width = Dim.Auto (),
             Height = Dim.Auto (),
             CheckedState = foregroundColorPicker.Style.ShowTextFields ? CheckState.Checked : CheckState.UnChecked,

Examples/UICatalog/Scenarios/Dialogs.cs

@@ -151,18 +151,15 @@ public class Dialogs : Scenario
         };
         frame.Add (label);
 
-        // Add hotkeys
-        var labels = Enum.GetNames<Alignment> ().Select (n => n = "_" + n);
-        var alignmentGroup = new RadioGroup
+        OptionSelector<Alignment> alignmentOptionSelector = new ()
         {
             X = Pos.Right (label) + 1,
             Y = Pos.Top (label),
-            RadioLabels = labels.ToArray (),
             Title = "Ali_gn",
-            BorderStyle = LineStyle.Dashed
+            AssignHotKeys = true
         };
-        frame.Add (alignmentGroup);
-        alignmentGroup.SelectedItem = labels.ToList ().IndexOf ("_" + Dialog.DefaultButtonAlignment.ToString ());
+        frame.Add (alignmentOptionSelector);
+        alignmentOptionSelector.Value = Dialog.DefaultButtonAlignment;
 
         frame.ValidatePosDim = true;
 
@@ -192,7 +189,7 @@ public class Dialogs : Scenario
                                                                       titleEdit,
                                                                       numButtonsEdit,
                                                                       glyphsNotWords,
-                                                                      alignmentGroup,
+                                                                      alignmentOptionSelector,
                                                                       buttonPressedLabel
                                                                      );
                                        Application.Run (dlg);
@@ -216,7 +213,7 @@ public class Dialogs : Scenario
         TextField titleEdit,
         TextField numButtonsEdit,
         CheckBox glyphsNotWords,
-        RadioGroup alignmentRadioGroup,
+        OptionSelector alignmentGroup,
         Label buttonPressedLabel
     )
     {
@@ -269,7 +266,7 @@ public class Dialogs : Scenario
             {
                 Title = titleEdit.Text,
                 Text = "Dialog Text",
-                ButtonAlignment = (Alignment)Enum.Parse (typeof (Alignment), alignmentRadioGroup.RadioLabels [alignmentRadioGroup.SelectedItem].Substring (1)),
+                ButtonAlignment = (Alignment)Enum.Parse (typeof (Alignment), alignmentGroup.Labels! [(int)alignmentGroup.Value!.Value] [1..]),
 
                 Buttons = buttons.ToArray ()
             };

Examples/UICatalog/Scenarios/DimAutoDemo.cs

@@ -56,7 +56,7 @@ public class DimAutoDemo : Scenario
             Width = Dim.Auto (DimAutoStyle.Content, minimumContentDim: Dim.Percent (25)),
             Height = Dim.Auto (DimAutoStyle.Content, minimumContentDim: 10)
         };
-        dimAutoFrameView.Margin.Thickness = new Thickness (1);
+        dimAutoFrameView.Margin!.Thickness = new Thickness (1);
         dimAutoFrameView.ValidatePosDim = true;
 
         var textEdit = new TextView
@@ -163,15 +163,15 @@ public class DimAutoDemo : Scenario
         dimAutoFrameView.Add (resetButton);
 
 
-        var radioGroup = new RadioGroup ()
+        var optionSelector = new OptionSelector ()
         {
-            RadioLabels = ["One", "Two", "Three"],
+            Labels = ["One", "Two", "Three"],
             X = 0,
             Y = Pos.AnchorEnd (),
-            Title = "Radios",
+            Title = "Options",
             BorderStyle = LineStyle.Dotted
         };
-        dimAutoFrameView.Add (radioGroup);
+        dimAutoFrameView.Add (optionSelector);
         return dimAutoFrameView;
     }
 

Examples/UICatalog/Scenarios/DynamicMenuBar.cs

@@ -174,11 +174,11 @@ public class DynamicMenuBar : Scenario
 
             var rChkLabels = new [] { "NoCheck", "Checked", "Radio" };
 
-            RbChkStyle = new ()
+            OsChkStyle = new ()
             {
-                X = Pos.Left (lblTitle), Y = Pos.Bottom (CkbSubMenu) + 1, RadioLabels = rChkLabels
+                X = Pos.Left (lblTitle), Y = Pos.Bottom (CkbSubMenu) + 1, Labels = rChkLabels
             };
-            Add (RbChkStyle);
+            Add (OsChkStyle);
 
             var lblShortcut = new Label
             {
@@ -294,7 +294,7 @@ public class DynamicMenuBar : Scenario
         public CheckBox CkbIsTopLevel { get; }
         public CheckBox CkbNullCheck { get; }
         public CheckBox CkbSubMenu { get; }
-        public RadioGroup RbChkStyle { get; }
+        public OptionSelector OsChkStyle { get; }
         public TextView TextAction { get; }
         public TextField TextHelp { get; }
         public TextField TextHotKey { get; }
@@ -361,7 +361,7 @@ public class DynamicMenuBar : Scenario
             CkbNullCheck.CheckedState = menuItem.AllowNullChecked ? CheckState.Checked : CheckState.UnChecked;
             TextHelp.Enabled = CkbSubMenu.CheckedState == CheckState.UnChecked;
             TextAction.Enabled = CkbSubMenu.CheckedState == CheckState.UnChecked;
-            RbChkStyle.SelectedItem = (int)(menuItem?.CheckType ?? MenuItemCheckStyle.NoCheck);
+            OsChkStyle.Value = (int)(menuItem?.CheckType ?? MenuItemCheckStyle.NoCheck);
             TextShortcutKey.Text = menuItem?.ShortcutTag ?? "";
 
             TextShortcutKey.Enabled = CkbIsTopLevel.CheckedState == CheckState.Checked && CkbSubMenu.CheckedState == CheckState.UnChecked
@@ -434,8 +434,8 @@ public class DynamicMenuBar : Scenario
                     HotKey = TextHotKey.Text,
                     IsTopLevel = CkbIsTopLevel?.CheckedState == CheckState.Checked,
                     HasSubMenu = CkbSubMenu?.CheckedState == CheckState.Checked,
-                    CheckStyle = RbChkStyle.SelectedItem == 0 ? MenuItemCheckStyle.NoCheck :
-                                 RbChkStyle.SelectedItem == 1 ? MenuItemCheckStyle.Checked :
+                    CheckStyle = OsChkStyle.Value == 0 ? MenuItemCheckStyle.NoCheck :
+                                 OsChkStyle.Value == 1 ? MenuItemCheckStyle.Checked :
                                  MenuItemCheckStyle.Radio,
                     ShortcutKey = TextShortcutKey.Text,
                     AllowNullChecked = CkbNullCheck?.CheckedState == CheckState.Checked,
@@ -484,7 +484,7 @@ public class DynamicMenuBar : Scenario
             TextHotKey.Text = "";
             CkbIsTopLevel.CheckedState = CheckState.UnChecked;
             CkbSubMenu.CheckedState = CheckState.UnChecked;
-            RbChkStyle.SelectedItem = (int)MenuItemCheckStyle.NoCheck;
+            OsChkStyle.Value = (int)MenuItemCheckStyle.NoCheck;
             TextShortcutKey.Text = "";
         }
 
@@ -829,9 +829,9 @@ public class DynamicMenuBar : Scenario
                                          HotKey = frmMenuDetails.TextHotKey.Text,
                                          IsTopLevel = frmMenuDetails.CkbIsTopLevel?.CheckedState == CheckState.Checked,
                                          HasSubMenu = frmMenuDetails.CkbSubMenu?.CheckedState == CheckState.Checked,
-                                         CheckStyle = frmMenuDetails.RbChkStyle.SelectedItem == 0
+                                         CheckStyle = frmMenuDetails.OsChkStyle.Value == 0
                                                           ? MenuItemCheckStyle.NoCheck
-                                                          : frmMenuDetails.RbChkStyle.SelectedItem == 1
+                                                          : frmMenuDetails.OsChkStyle.Value == 1
                                                               ? MenuItemCheckStyle.Checked
                                                               : MenuItemCheckStyle.Radio,
                                          ShortcutKey = frmMenuDetails.TextShortcutKey.Text

Examples/UICatalog/Scenarios/EditorsAndHelpers/AdornmentsEditor.cs

@@ -99,7 +99,7 @@ public class AdornmentsEditor : EditorBase
             SuperViewRendersLineCanvas = true,
             BorderStyle = LineStyle.Single
         };
-        MarginEditor.Border!.Thickness = MarginEditor.Border.Thickness with { Bottom = 0 };
+        MarginEditor.Border!.Thickness = MarginEditor.Border!.Thickness with { Bottom = 0 };
         Add (MarginEditor);
 
         BorderEditor = new ()
@@ -109,7 +109,7 @@ public class AdornmentsEditor : EditorBase
             SuperViewRendersLineCanvas = true,
             BorderStyle = LineStyle.Single
         };
-        BorderEditor.Border!.Thickness = BorderEditor.Border.Thickness with { Bottom = 0 };
+        BorderEditor.Border!.Thickness = BorderEditor.Border!.Thickness with { Bottom = 0 };
         Add (BorderEditor);
 
         PaddingEditor = new ()
@@ -119,7 +119,7 @@ public class AdornmentsEditor : EditorBase
             SuperViewRendersLineCanvas = true,
             BorderStyle = LineStyle.Single
         };
-        PaddingEditor.Border!.Thickness = PaddingEditor.Border.Thickness with { Bottom = 0 };
+        PaddingEditor.Border!.Thickness = PaddingEditor.Border!.Thickness with { Bottom = 0 };
         Add (PaddingEditor);
 
         Width = Dim.Auto (maximumContentDim: Dim.Func (_ => MarginEditor.Frame.Width - 2));

Examples/UICatalog/Scenarios/EditorsAndHelpers/ArrangementEditor.cs

@@ -1,7 +1,4 @@
 #nullable enable
-using System;
-using System.Collections.Generic;
-
 namespace UICatalog.Scenarios;
 
 /// <summary>
@@ -16,92 +13,34 @@ public sealed class ArrangementEditor : EditorBase
 
         Initialized += ArrangementEditor_Initialized;
 
-        _arrangementSlider.Options =
-        [
-            new SliderOption<ViewArrangement>
-            {
-                Legend = ViewArrangement.Movable.ToString (),
-                Data = ViewArrangement.Movable
-            },
-
-            new SliderOption<ViewArrangement>
-            {
-                Legend = ViewArrangement.LeftResizable.ToString (),
-                Data = ViewArrangement.LeftResizable
-            },
-
-            new SliderOption<ViewArrangement>
-            {
-                Legend = ViewArrangement.RightResizable.ToString (),
-                Data = ViewArrangement.RightResizable
-            },
-
-            new SliderOption<ViewArrangement>
-            {
-                Legend = ViewArrangement.TopResizable.ToString (),
-                Data = ViewArrangement.TopResizable
-            },
-
-            new SliderOption<ViewArrangement>
-            {
-                Legend = ViewArrangement.BottomResizable.ToString (),
-                Data = ViewArrangement.BottomResizable
-            },
-
-            new SliderOption<ViewArrangement>
-            {
-                Legend = ViewArrangement.Overlapped.ToString (),
-                Data = ViewArrangement.Overlapped
-            }
-        ];
-
-        Add (_arrangementSlider);
+        Add (_arrangementSelector);
     }
 
-    private readonly Slider<ViewArrangement> _arrangementSlider = new()
+    private readonly FlagSelector<ViewArrangement> _arrangementSelector = new ()
     {
-        Orientation = Orientation.Vertical,
-        UseMinimumSize = true,
-        Type = SliderType.Multiple,
-        AllowEmpty = true,
+        Orientation = Orientation.Vertical
     };
 
     protected override void OnViewToEditChanged ()
     {
-        _arrangementSlider.Enabled = ViewToEdit is not Adornment;
+        _arrangementSelector.Enabled = ViewToEdit is not Adornment;
 
-        _arrangementSlider.OptionsChanged -= ArrangementSliderOnOptionsChanged;
+        _arrangementSelector.ValueChanged -= ArrangementFlagsOnValueChanged;
 
         // Set the appropriate options in the slider based on _viewToEdit.Arrangement
         if (ViewToEdit is { })
         {
-            _arrangementSlider.Options.ForEach (
-                                                option =>
-                                                {
-                                                    _arrangementSlider.ChangeOption (
-                                                                                     _arrangementSlider.Options.IndexOf (option),
-                                                                                     (ViewToEdit.Arrangement & option.Data) == option.Data);
-                                                });
+            _arrangementSelector.Value = ViewToEdit.Arrangement;
         }
 
-        _arrangementSlider.OptionsChanged += ArrangementSliderOnOptionsChanged;
+        _arrangementSelector.ValueChanged += ArrangementFlagsOnValueChanged;
     }
 
-    private void ArrangementEditor_Initialized (object? sender, EventArgs e) { _arrangementSlider.OptionsChanged += ArrangementSliderOnOptionsChanged; }
-
-    private void ArrangementSliderOnOptionsChanged (object? sender, SliderEventArgs<ViewArrangement> e)
+    private void ArrangementFlagsOnValueChanged (object? sender, EventArgs<ViewArrangement?> e)
     {
-        if (ViewToEdit is { })
+        if (ViewToEdit is { } && e.Value is { })
         {
-            // Set the arrangement based on the selected options
-            var arrangement = ViewArrangement.Fixed;
-
-            foreach (KeyValuePair<int, SliderOption<ViewArrangement>> option in e.Options)
-            {
-                arrangement |= option.Value.Data;
-            }
-
-            ViewToEdit.Arrangement = arrangement;
+            ViewToEdit.Arrangement = (ViewArrangement)e.Value;
 
             if (ViewToEdit.Arrangement.HasFlag (ViewArrangement.Overlapped))
             {
@@ -114,14 +53,9 @@ public sealed class ArrangementEditor : EditorBase
                 ViewToEdit.SchemeName = ViewToEdit!.SuperView!.SchemeName;
             }
 
-            if (ViewToEdit.Arrangement.HasFlag (ViewArrangement.Movable))
-            {
-                ViewToEdit.BorderStyle = LineStyle.Double;
-            }
-            else
-            {
-                ViewToEdit.BorderStyle = LineStyle.Single;
-            }
+            ViewToEdit.BorderStyle = ViewToEdit.Arrangement.HasFlag (ViewArrangement.Movable) ? LineStyle.Double : LineStyle.Single;
         }
     }
+
+    private void ArrangementEditor_Initialized (object? sender, EventArgs e) { _arrangementSelector.ValueChanged += ArrangementFlagsOnValueChanged; }
 }

Examples/UICatalog/Scenarios/EditorsAndHelpers/BorderEditor.cs

@@ -8,7 +8,7 @@ namespace UICatalog.Scenarios;
 public class BorderEditor : AdornmentEditor
 {
     private CheckBox? _ckbTitle;
-    private RadioGroup? _rbBorderStyle;
+    private OptionSelector<LineStyle>? _osBorderStyle;
     private CheckBox? _ckbGradient;
 
     public BorderEditor ()
@@ -21,34 +21,31 @@ public class BorderEditor : AdornmentEditor
     private void BorderEditor_AdornmentChanged (object? sender, EventArgs e)
     {
         _ckbTitle!.CheckedState = ((Border)AdornmentToEdit!).Settings.FastHasFlags (BorderSettings.Title) ? CheckState.Checked : CheckState.UnChecked;
-        _rbBorderStyle!.SelectedItem = (int)((Border)AdornmentToEdit).LineStyle;
+        _osBorderStyle!.Value = ((Border)AdornmentToEdit).LineStyle;
         _ckbGradient!.CheckedState = ((Border)AdornmentToEdit).Settings.FastHasFlags (BorderSettings.Gradient) ? CheckState.Checked : CheckState.UnChecked;
     }
 
     private void BorderEditor_Initialized (object? sender, EventArgs e)
     {
-        List<LineStyle> borderStyleEnum = Enum.GetValues (typeof (LineStyle)).Cast<LineStyle> ().ToList ();
-
-        _rbBorderStyle = new ()
+        _osBorderStyle = new ()
         {
             X = 0,
 
-            Y = Pos.Bottom (SubViews.ToArray() [^1]),
+            Y = Pos.Bottom (SubViews.ToArray () [^1]),
             Width = Dim.Fill (),
-            SelectedItem = (int)(((Border)AdornmentToEdit!)?.LineStyle ?? LineStyle.None),
+            Value = ((Border)AdornmentToEdit!)?.LineStyle ?? LineStyle.None,
             BorderStyle = LineStyle.Single,
             Title = "Border St_yle",
             SuperViewRendersLineCanvas = true,
-            RadioLabels = borderStyleEnum.Select (style => style.ToString ()).ToArray ()
         };
-        Add (_rbBorderStyle);
+        Add (_osBorderStyle);
 
-        _rbBorderStyle.SelectedItemChanged += OnRbBorderStyleOnSelectedItemChanged;
+        _osBorderStyle.ValueChanged += OnRbBorderStyleOnValueChanged;
 
         _ckbTitle = new ()
         {
             X = 0,
-            Y = Pos.Bottom (_rbBorderStyle),
+            Y = Pos.Bottom (_osBorderStyle),
 
             CheckedState = CheckState.Checked,
             SuperViewRendersLineCanvas = true,
@@ -73,10 +70,14 @@ public class BorderEditor : AdornmentEditor
 
         return;
 
-        void OnRbBorderStyleOnSelectedItemChanged (object? s, SelectedItemChangedArgs args)
+        void OnRbBorderStyleOnValueChanged (object? s, EventArgs<LineStyle?> args)
         {
             LineStyle prevBorderStyle = AdornmentToEdit!.BorderStyle;
-            ((Border)AdornmentToEdit).LineStyle = (LineStyle)args.SelectedItem!;
+
+            if (args.Value is { })
+            {
+                ((Border)AdornmentToEdit).LineStyle = (LineStyle)args.Value;
+            }
 
             if (((Border)AdornmentToEdit).LineStyle == LineStyle.None)
             {

Examples/UICatalog/Scenarios/EditorsAndHelpers/DimEditor.cs

@@ -18,7 +18,7 @@ public class DimEditor : EditorBase
     }
 
     private int _value;
-    private RadioGroup? _dimRadioGroup;
+    private OptionSelector? _dimOptionSelector;
     private TextField? _valueEdit;
 
     /// <inheritdoc />
@@ -44,7 +44,7 @@ public class DimEditor : EditorBase
 
         try
         {
-            _dimRadioGroup!.SelectedItem = _dimNames.IndexOf (_dimNames.First (s => dim!.ToString ().StartsWith (s)));
+            _dimOptionSelector!.Value = _dimNames.IndexOf (_dimNames.First (s => dim!.ToString ().StartsWith (s)));
         }
         catch (InvalidOperationException e)
         {
@@ -92,13 +92,13 @@ public class DimEditor : EditorBase
             Text = $"{Title}:"
         };
         Add (label);
-        _dimRadioGroup = new () { X = 0, Y = Pos.Bottom (label), RadioLabels = _radioItems };
-        _dimRadioGroup.SelectedItemChanged += OnRadioGroupOnSelectedItemChanged;
+        _dimOptionSelector = new () { X = 0, Y = Pos.Bottom (label), Labels = _optionLabels };
+        _dimOptionSelector.ValueChanged += OnOptionSelectorOnValueChanged;
         _valueEdit = new ()
         {
             X = Pos.Right (label) + 1,
             Y = 0,
-            Width = Dim.Func (_ => _radioItems.Max (i => i.GetColumns ()) - label.Frame.Width + 1),
+            Width = Dim.Func (_ => _optionLabels.Max (i => i.GetColumns ()) - label.Frame.Width + 1),
             Text = $"{_value}"
         };
 
@@ -117,15 +117,15 @@ public class DimEditor : EditorBase
         };
         Add (_valueEdit);
 
-        Add (_dimRadioGroup);
+        Add (_dimOptionSelector);
 
     }
 
-    private void OnRadioGroupOnSelectedItemChanged (object? s, SelectedItemChangedArgs selected) { DimChanged (); }
+    private void OnOptionSelectorOnValueChanged (object? s, EventArgs<int?> selected) { DimChanged (); }
 
     // These need to have same order 
     private readonly List<string> _dimNames = ["Absolute", "Auto", "Fill", "Func", "Percent",];
-    private readonly string [] _radioItems = ["Absolute(n)", "Auto", "Fill(n)", "Func(()=>n)", "Percent(n)",];
+    private readonly string [] _optionLabels = ["Absolute(n)", "Auto", "Fill(n)", "Func(()=>n)", "Percent(n)",];
 
     private void DimChanged ()
     {
@@ -136,7 +136,7 @@ public class DimEditor : EditorBase
 
         try
         {
-            Dim? dim = _dimRadioGroup!.SelectedItem switch
+            Dim? dim = _dimOptionSelector!.Value switch
             {
                 0 => Dim.Absolute (_value),
                 1 => Dim.Auto (),

Examples/UICatalog/Scenarios/EditorsAndHelpers/MarginEditor.cs

@@ -12,7 +12,7 @@ public class MarginEditor : AdornmentEditor
         AdornmentChanged += MarginEditor_AdornmentChanged;
     }
 
-    private RadioGroup? _rgShadow;
+    private OptionSelector<ShadowStyle>? _optionsShadow;
 
     private FlagSelector? _flagSelectorTransparent;
 
@@ -20,18 +20,18 @@ public class MarginEditor : AdornmentEditor
     {
         if (AdornmentToEdit is { })
         {
-            _rgShadow!.SelectedItem = (int)((Margin)AdornmentToEdit).ShadowStyle;
+            _optionsShadow!.Value = ((Margin)AdornmentToEdit).ShadowStyle;
         }
 
         if (AdornmentToEdit is { })
         {
-            _flagSelectorTransparent!.Value = (uint)((Margin)AdornmentToEdit).ViewportSettings;
+            _flagSelectorTransparent!.Value = (int)((Margin)AdornmentToEdit).ViewportSettings;
         }
     }
 
     private void MarginEditor_Initialized (object? sender, EventArgs e)
     {
-        _rgShadow = new RadioGroup
+        _optionsShadow = new ()
         {
             X = 0,
             Y = Pos.Bottom (SubViews.ElementAt(SubViews.Count-1)),
@@ -39,44 +39,36 @@ public class MarginEditor : AdornmentEditor
             SuperViewRendersLineCanvas = true,
             Title = "_Shadow",
             BorderStyle = LineStyle.Single,
-            RadioLabels = Enum.GetNames (typeof (ShadowStyle)),
+            AssignHotKeys = true
         };
 
         if (AdornmentToEdit is { })
         {
-            _rgShadow.SelectedItem = (int)((Margin)AdornmentToEdit).ShadowStyle;
+            _optionsShadow.Value = ((Margin)AdornmentToEdit).ShadowStyle;
         }
 
-        _rgShadow.SelectedItemChanged += (_, args) =>
-                                        {
-                                            ((Margin)AdornmentToEdit!).ShadowStyle = (ShadowStyle)args.SelectedItem!;
-                                        };
+        _optionsShadow.ValueChanged += (_, args) => ((Margin)AdornmentToEdit!).ShadowStyle = args.Value!.Value;
 
-        Add (_rgShadow);
+        Add (_optionsShadow);
 
-        var flags = new Dictionary<uint, string> ()
-        {
-            { (uint)Terminal.Gui.ViewBase.ViewportSettingsFlags.Transparent, "Transparent" },
-            { (uint)Terminal.Gui.ViewBase.ViewportSettingsFlags.TransparentMouse, "TransparentMouse" }
-        };
-
-        _flagSelectorTransparent = new FlagSelector ()
+        _flagSelectorTransparent = new FlagSelector<ViewportSettingsFlags> ()
         {
             X = 0,
-            Y = Pos.Bottom (_rgShadow),
+            Y = Pos.Bottom (_optionsShadow),
 
             SuperViewRendersLineCanvas = true,
             Title = "_ViewportSettings",
             BorderStyle = LineStyle.Single,
         };
-        _flagSelectorTransparent.SetFlags(flags.AsReadOnly ());
-
+        _flagSelectorTransparent.Values = [(int)ViewportSettingsFlags.Transparent, (int)ViewportSettingsFlags.TransparentMouse];
+        _flagSelectorTransparent.Labels = ["Transparent", "TransparentMouse"];
+        _flagSelectorTransparent.AssignHotKeys = true;
 
         Add (_flagSelectorTransparent);
 
         if (AdornmentToEdit is { })
         {
-            _flagSelectorTransparent.Value = (uint)((Margin)AdornmentToEdit).ViewportSettings;
+            _flagSelectorTransparent.Value = (int)((Margin)AdornmentToEdit).ViewportSettings;
         }
 
         _flagSelectorTransparent.ValueChanged += (_, args) =>

Examples/UICatalog/Scenarios/EditorsAndHelpers/PosEditor.cs

@@ -19,7 +19,7 @@ public class PosEditor : EditorBase
     }
 
     private int _value;
-    private RadioGroup? _posRadioGroup;
+    private OptionSelector? _posOptionSelector;
     private TextField? _valueEdit;
 
     protected override void OnUpdateLayoutSettings ()
@@ -44,7 +44,7 @@ public class PosEditor : EditorBase
 
         try
         {
-            _posRadioGroup!.SelectedItem = _posNames.IndexOf (_posNames.First (s => pos.ToString ().Contains (s)));
+            _posOptionSelector!.Value = _posNames.IndexOf (_posNames.First (s => pos.ToString ().Contains (s)));
         }
         catch (InvalidOperationException e)
         {
@@ -91,14 +91,14 @@ public class PosEditor : EditorBase
             Text = $"{Title}:"
         };
         Add (label);
-        _posRadioGroup = new () { X = 0, Y = Pos.Bottom (label), RadioLabels = _radioItems };
-        _posRadioGroup.SelectedItemChanged += OnRadioGroupOnSelectedItemChanged;
+        _posOptionSelector = new () { X = 0, Y = Pos.Bottom (label), Labels = _optionLabels };
+        _posOptionSelector.ValueChanged += OnOptionSelectorOnValueChanged;
 
         _valueEdit = new ()
         {
             X = Pos.Right (label) + 1,
             Y = 0,
-            Width = Dim.Func (_ => _radioItems.Max (i => i.GetColumns ()) - label.Frame.Width + 1),
+            Width = Dim.Func (_ => _optionLabels.Max (i => i.GetColumns ()) - label.Frame.Width + 1),
             Text = $"{_value}"
         };
 
@@ -118,14 +118,14 @@ public class PosEditor : EditorBase
                                 };
         Add (_valueEdit);
 
-        Add (_posRadioGroup);
+        Add (_posOptionSelector);
     }
 
-    private void OnRadioGroupOnSelectedItemChanged (object? s, SelectedItemChangedArgs selected) { PosChanged (); }
+    private void OnOptionSelectorOnValueChanged (object? s, EventArgs<int?> selected) { PosChanged (); }
 
     // These need to have same order 
     private readonly List<string> _posNames = ["Absolute", "Align", "AnchorEnd", "Center", "Func", "Percent"];
-    private readonly string [] _radioItems = ["Absolute(n)", "Align", "AnchorEnd", "Center", "Func(()=>n)", "Percent(n)"];
+    private readonly string [] _optionLabels = ["Absolute(n)", "Align", "AnchorEnd", "Center", "Func(()=>n)", "Percent(n)"];
 
     private void PosChanged ()
     {
@@ -136,7 +136,7 @@ public class PosEditor : EditorBase
 
         try
         {
-            Pos? pos = _posRadioGroup!.SelectedItem switch
+            Pos? pos = _posOptionSelector!.Value switch
                        {
                            0 => Pos.Absolute (_value),
                            1 => Pos.Align (Alignment.Start),

Examples/UICatalog/Scenarios/EditorsAndHelpers/ViewPropertiesEditor.cs

@@ -6,7 +6,7 @@ public class ViewPropertiesEditor : EditorBase
 {
     private CheckBox? _canFocusCheckBox;
     private CheckBox? _enabledCheckBox;
-    private RadioGroup? _orientation;
+    private OptionSelector<Orientation>? _orientationOptionSelector;
     private TextView? _text;
 
     /// <inheritdoc/>
@@ -48,24 +48,23 @@ public class ViewPropertiesEditor : EditorBase
 
         Label label = new () { X = Pos.Right (_enabledCheckBox) + 1, Y = Pos.Top (_enabledCheckBox), Text = "Orientation:" };
 
-        _orientation = new ()
+        _orientationOptionSelector = new ()
         {
             X = Pos.Right (label) + 1,
             Y = Pos.Top (label),
-            RadioLabels = new [] { "Horizontal", "Vertical" },
             Orientation = Orientation.Horizontal
         };
 
-        _orientation.SelectedItemChanged += (s, selected) =>
+        _orientationOptionSelector.ValueChanged += (s, selected) =>
                                             {
                                                 if (ViewToEdit is IOrientation orientatedView)
                                                 {
-                                                    orientatedView.Orientation = (Orientation)_orientation.SelectedItem!;
+                                                    orientatedView.Orientation = _orientationOptionSelector.Value!.Value;
                                                 }
                                             };
-        Add (label, _orientation);
+        Add (label, _orientationOptionSelector);
 
-        label = new () { X = 0, Y = Pos.Bottom (_orientation), Text = "Text:" };
+        label = new () { X = 0, Y = Pos.Bottom (_orientationOptionSelector), Text = "Text:" };
 
         _text = new ()
         {
@@ -114,12 +113,12 @@ public class ViewPropertiesEditor : EditorBase
 
             if (ViewToEdit is IOrientation orientatedView)
             {
-                _orientation!.SelectedItem = (int)orientatedView.Orientation;
-                _orientation.Enabled = true;
+                _orientationOptionSelector!.Value = orientatedView.Orientation;
+                _orientationOptionSelector.Enabled = true;
             }
             else
             {
-                _orientation!.Enabled = false;
+                _orientationOptionSelector!.Enabled = false;
             }
         }
     }

Examples/UICatalog/Scenarios/FileDialogExamples.cs

@@ -1,8 +1,4 @@
-using System;
-using System.IO;
-using System.IO.Abstractions;
-using System.Linq;
-using System.Text;
+using System.IO.Abstractions;
 
 namespace UICatalog.Scenarios;
 
@@ -20,10 +16,10 @@ public class FileDialogExamples : Scenario
     private CheckBox _cbMustExist;
     private CheckBox _cbShowTreeBranchLines;
     private CheckBox _cbUseColors;
-    private RadioGroup _rgAllowedTypes;
-    private RadioGroup _rgCaption;
-    private RadioGroup _rgIcons;
-    private RadioGroup _rgOpenMode;
+    private OptionSelector _osAllowedTypes;
+    private OptionSelector _osCaption;
+    private OptionSelector _osIcons;
+    private OptionSelector _osOpenMode;
     private TextField _tbCancelButton;
     private TextField _tbOkButton;
 
@@ -34,28 +30,29 @@ public class FileDialogExamples : Scenario
         var x = 1;
         var win = new Window { Title = GetQuitKeyAndName () };
 
-        _cbMustExist = new CheckBox { CheckedState = CheckState.Checked, Y = y++, X = x, Text = "Must E_xist" };
+        _cbMustExist = new () { CheckedState = CheckState.Checked, Y = y++, X = x, Text = "Must E_xist" };
         win.Add (_cbMustExist);
 
-        _cbUseColors = new CheckBox { CheckedState = FileDialogStyle.DefaultUseColors ? CheckState.Checked : CheckState.UnChecked, Y = y++, X = x, Text = "_Use Colors" };
+        _cbUseColors = new ()
+            { CheckedState = FileDialogStyle.DefaultUseColors ? CheckState.Checked : CheckState.UnChecked, Y = y++, X = x, Text = "_Use Colors" };
         win.Add (_cbUseColors);
 
-        _cbCaseSensitive = new CheckBox { CheckedState = CheckState.UnChecked, Y = y++, X = x, Text = "_Case Sensitive Search" };
+        _cbCaseSensitive = new () { CheckedState = CheckState.UnChecked, Y = y++, X = x, Text = "_Case Sensitive Search" };
         win.Add (_cbCaseSensitive);
 
-        _cbAllowMultipleSelection = new CheckBox { CheckedState = CheckState.UnChecked, Y = y++, X = x, Text = "_Multiple" };
+        _cbAllowMultipleSelection = new () { CheckedState = CheckState.UnChecked, Y = y++, X = x, Text = "_Multiple" };
         win.Add (_cbAllowMultipleSelection);
 
-        _cbShowTreeBranchLines = new CheckBox { CheckedState = CheckState.Checked, Y = y++, X = x, Text = "Tree Branch _Lines" };
+        _cbShowTreeBranchLines = new () { CheckedState = CheckState.Checked, Y = y++, X = x, Text = "Tree Branch _Lines" };
         win.Add (_cbShowTreeBranchLines);
 
-        _cbAlwaysTableShowHeaders = new CheckBox { CheckedState = CheckState.Checked, Y = y++, X = x, Text = "Always Show _Headers" };
+        _cbAlwaysTableShowHeaders = new () { CheckedState = CheckState.Checked, Y = y++, X = x, Text = "Always Show _Headers" };
         win.Add (_cbAlwaysTableShowHeaders);
 
-        _cbDrivesOnlyInTree = new CheckBox { CheckedState = CheckState.UnChecked, Y = y++, X = x, Text = "Only Show _Drives" };
+        _cbDrivesOnlyInTree = new () { CheckedState = CheckState.UnChecked, Y = y++, X = x, Text = "Only Show _Drives" };
         win.Add (_cbDrivesOnlyInTree);
 
-        _cbPreserveFilenameOnDirectoryChanges = new CheckBox { CheckedState = CheckState.UnChecked, Y = y++, X = x, Text = "Preserve Filename" };
+        _cbPreserveFilenameOnDirectoryChanges = new () { CheckedState = CheckState.UnChecked, Y = y++, X = x, Text = "Preserve Filename" };
         win.Add (_cbPreserveFilenameOnDirectoryChanges);
 
         y = 0;
@@ -66,9 +63,9 @@ public class FileDialogExamples : Scenario
                 );
         win.Add (new Label { X = x++, Y = y++, Text = "Caption" });
 
-        _rgCaption = new RadioGroup { X = x, Y = y };
-        _rgCaption.RadioLabels = new [] { "_Ok", "O_pen", "_Save" };
-        win.Add (_rgCaption);
+        _osCaption = new () { X = x, Y = y };
+        _osCaption.Labels = ["_Ok", "O_pen", "_Save"];
+        win.Add (_osCaption);
 
         y = 0;
         x = 34;
@@ -78,9 +75,9 @@ public class FileDialogExamples : Scenario
                 );
         win.Add (new Label { X = x++, Y = y++, Text = "OpenMode" });
 
-        _rgOpenMode = new RadioGroup { X = x, Y = y };
-        _rgOpenMode.RadioLabels = new [] { "_File", "D_irectory", "_Mixed" };
-        win.Add (_rgOpenMode);
+        _osOpenMode = new () { X = x, Y = y };
+        _osOpenMode.Labels = ["_File", "D_irectory", "_Mixed"];
+        win.Add (_osOpenMode);
 
         y = 0;
         x = 48;
@@ -90,9 +87,9 @@ public class FileDialogExamples : Scenario
                 );
         win.Add (new Label { X = x++, Y = y++, Text = "Icons" });
 
-        _rgIcons = new RadioGroup { X = x, Y = y };
-        _rgIcons.RadioLabels = new [] { "_None", "_Unicode", "Nerd_*" };
-        win.Add (_rgIcons);
+        _osIcons = new () { X = x, Y = y };
+        _osIcons.Labels = ["_None", "_Unicode", "Nerd_*"];
+        win.Add (_osIcons);
 
         win.Add (new Label { Y = Pos.AnchorEnd (2), Text = "* Requires installing Nerd fonts" });
         win.Add (new Label { Y = Pos.AnchorEnd (1), Text = "  (see: https://github.com/devblackops/Terminal-Icons)" });
@@ -105,9 +102,9 @@ public class FileDialogExamples : Scenario
                 );
         win.Add (new Label { X = x++, Y = y++, Text = "Allowed" });
 
-        _rgAllowedTypes = new RadioGroup { X = x, Y = y };
-        _rgAllowedTypes.RadioLabels = new [] { "An_y", "Cs_v (Recommended)", "Csv (S_trict)" };
-        win.Add (_rgAllowedTypes);
+        _osAllowedTypes = new () { X = x, Y = y };
+        _osAllowedTypes.Labels = ["An_y", "Cs_v (Recommended)", "Csv (S_trict)"];
+        win.Add (_osAllowedTypes);
 
         y = 5;
         x = 45;
@@ -118,31 +115,31 @@ public class FileDialogExamples : Scenario
         win.Add (new Label { X = x++, Y = y++, Text = "Buttons" });
 
         win.Add (new Label { X = x, Y = y++, Text = "O_k Text:" });
-        _tbOkButton = new TextField { X = x, Y = y++, Width = 12 };
+        _tbOkButton = new () { X = x, Y = y++, Width = 12 };
         win.Add (_tbOkButton);
         win.Add (new Label { X = x, Y = y++, Text = "_Cancel Text:" });
-        _tbCancelButton = new TextField { X = x, Y = y++, Width = 12 };
+        _tbCancelButton = new () { X = x, Y = y++, Width = 12 };
         win.Add (_tbCancelButton);
-        _cbFlipButtonOrder = new CheckBox { X = x, Y = y++, Text = "Flip Ord_er" };
+        _cbFlipButtonOrder = new () { X = x, Y = y++, Text = "Flip Ord_er" };
         win.Add (_cbFlipButtonOrder);
 
         var btn = new Button { X = 1, Y = 9, IsDefault = true, Text = "Run Dialog" };
 
         win.Accepting += (s, e) =>
-                        {
-                            try
-                            {
-                                CreateDialog ();
-                            }
-                            catch (Exception ex)
-                            {
-                                MessageBox.ErrorQuery ("Error", ex.ToString (), "_Ok");
-                            }
-                            finally
-                            {
-                                e.Handled = true;
-                            }
-                        };
+                         {
+                             try
+                             {
+                                 CreateDialog ();
+                             }
+                             catch (Exception ex)
+                             {
+                                 MessageBox.ErrorQuery ("Error", ex.ToString (), "_Ok");
+                             }
+                             finally
+                             {
+                                 e.Handled = true;
+                             }
+                         };
         win.Add (btn);
 
         Application.Run (win);
@@ -164,112 +161,115 @@ public class FileDialogExamples : Scenario
 
     private void CreateDialog ()
     {
-        var fd = new FileDialog
+        if (_osOpenMode.Value is { })
         {
-            OpenMode = Enum.Parse<OpenMode> (
-                                             _rgOpenMode.RadioLabels
-                                                        .Select (l => TextFormatter.FindHotKey (l, _rgOpenMode.HotKeySpecifier, out int hotPos, out Key _)
-
-                                                                          // Remove the hotkey specifier at the found position
-                                                                          ? TextFormatter.RemoveHotKeySpecifier (l, hotPos, _rgOpenMode.HotKeySpecifier)
-
-                                                                          // No hotkey found, return the label as is
-                                                                          : l)
-                                                        .ToArray () [_rgOpenMode.SelectedItem]
-                                            ),
-            MustExist = _cbMustExist.CheckedState == CheckState.Checked,
-            AllowsMultipleSelection = _cbAllowMultipleSelection.CheckedState == CheckState.Checked
-        };
+            var fd = new FileDialog
+            {
+                OpenMode = Enum.Parse<OpenMode> (
+                                                 _osOpenMode.Labels
+                                                            .Select (l => TextFormatter.FindHotKey (l, _osOpenMode.HotKeySpecifier, out int hotPos, out Key _)
+
+                                                                              // Remove the hotkey specifier at the found position
+                                                                              ? TextFormatter.RemoveHotKeySpecifier (l, hotPos, _osOpenMode.HotKeySpecifier)
+
+                                                                              // No hotkey found, return the label as is
+                                                                              : l)
+                                                            .ToArray () [_osOpenMode.Value.Value]
+                                                ),
+                MustExist = _cbMustExist.CheckedState == CheckState.Checked,
+                AllowsMultipleSelection = _cbAllowMultipleSelection.CheckedState == CheckState.Checked
+            };
+
+            fd.Style.OkButtonText =
+                _osCaption.Labels.Select (l => TextFormatter.RemoveHotKeySpecifier (l, 0, _osCaption.HotKeySpecifier)).ToArray ()
+                    [_osCaption.Value!.Value];
+
+            // If Save style dialog then give them an overwrite prompt
+            if (_osCaption.Value == 2)
+            {
+                fd.FilesSelected += ConfirmOverwrite;
+            }
 
-        fd.Style.OkButtonText = _rgCaption.RadioLabels.Select (l => TextFormatter.RemoveHotKeySpecifier(l, 0, _rgCaption.HotKeySpecifier)).ToArray() [_rgCaption.SelectedItem];
+            fd.Style.IconProvider.UseUnicodeCharacters = _osIcons.Value == 1;
+            fd.Style.IconProvider.UseNerdIcons = _osIcons.Value == 2;
 
-        // If Save style dialog then give them an overwrite prompt
-        if (_rgCaption.SelectedItem == 2)
-        {
-            fd.FilesSelected += ConfirmOverwrite;
-        }
-
-        fd.Style.IconProvider.UseUnicodeCharacters = _rgIcons.SelectedItem == 1;
-        fd.Style.IconProvider.UseNerdIcons = _rgIcons.SelectedItem == 2;
+            if (_cbCaseSensitive.CheckedState == CheckState.Checked)
+            {
+                fd.SearchMatcher = new CaseSensitiveSearchMatcher ();
+            }
 
-        if (_cbCaseSensitive.CheckedState == CheckState.Checked)
-        {
-            fd.SearchMatcher = new CaseSensitiveSearchMatcher ();
-        }
+            fd.Style.UseColors = _cbUseColors.CheckedState == CheckState.Checked;
 
-        fd.Style.UseColors = _cbUseColors.CheckedState == CheckState.Checked;
+            fd.Style.TreeStyle.ShowBranchLines = _cbShowTreeBranchLines.CheckedState == CheckState.Checked;
+            fd.Style.TableStyle.AlwaysShowHeaders = _cbAlwaysTableShowHeaders.CheckedState == CheckState.Checked;
 
-        fd.Style.TreeStyle.ShowBranchLines = _cbShowTreeBranchLines.CheckedState == CheckState.Checked;
-        fd.Style.TableStyle.AlwaysShowHeaders = _cbAlwaysTableShowHeaders.CheckedState == CheckState.Checked;
+            IDirectoryInfoFactory dirInfoFactory = new FileSystem ().DirectoryInfo;
 
-        IDirectoryInfoFactory dirInfoFactory = new FileSystem ().DirectoryInfo;
+            if (_cbDrivesOnlyInTree.CheckedState == CheckState.Checked)
+            {
+                fd.Style.TreeRootGetter = () => { return Environment.GetLogicalDrives ().ToDictionary (dirInfoFactory.New, k => k); };
+            }
 
-        if (_cbDrivesOnlyInTree.CheckedState == CheckState.Checked)
-        {
-            fd.Style.TreeRootGetter = () => { return Environment.GetLogicalDrives ().ToDictionary (dirInfoFactory.New, k => k); };
-        }
+            fd.Style.PreserveFilenameOnDirectoryChanges = _cbPreserveFilenameOnDirectoryChanges.CheckedState == CheckState.Checked;
 
-        fd.Style.PreserveFilenameOnDirectoryChanges = _cbPreserveFilenameOnDirectoryChanges.CheckedState == CheckState.Checked;
-        
+            if (_osAllowedTypes.Value > 0)
+            {
+                fd.AllowedTypes.Add (new AllowedType ("Data File", ".csv", ".tsv"));
 
-        if (_rgAllowedTypes.SelectedItem > 0)
-        {
-            fd.AllowedTypes.Add (new AllowedType ("Data File", ".csv", ".tsv"));
+                if (_osAllowedTypes.Value == 1)
+                {
+                    fd.AllowedTypes.Insert (1, new AllowedTypeAny ());
+                }
+            }
 
-            if (_rgAllowedTypes.SelectedItem == 1)
+            if (!string.IsNullOrWhiteSpace (_tbOkButton.Text))
             {
-                fd.AllowedTypes.Insert (1, new AllowedTypeAny ());
+                fd.Style.OkButtonText = _tbOkButton.Text;
             }
-        }
 
-        if (!string.IsNullOrWhiteSpace (_tbOkButton.Text))
-        {
-            fd.Style.OkButtonText = _tbOkButton.Text;
-        }
-
-        if (!string.IsNullOrWhiteSpace (_tbCancelButton.Text))
-        {
-            fd.Style.CancelButtonText = _tbCancelButton.Text;
-        }
-
-        if (_cbFlipButtonOrder.CheckedState == CheckState.Checked)
-        {
-            fd.Style.FlipOkCancelButtonLayoutOrder = true;
-        }
+            if (!string.IsNullOrWhiteSpace (_tbCancelButton.Text))
+            {
+                fd.Style.CancelButtonText = _tbCancelButton.Text;
+            }
 
-        Application.Run (fd);
+            if (_cbFlipButtonOrder.CheckedState == CheckState.Checked)
+            {
+                fd.Style.FlipOkCancelButtonLayoutOrder = true;
+            }
 
-        var canceled = fd.Canceled;
-        var multiSelected = fd.MultiSelected;
-        var path = fd.Path;
+            Application.Run (fd);
 
-        // This needs to be disposed before opening other toplevel
-        fd.Dispose ();
+            bool canceled = fd.Canceled;
+            IReadOnlyList<string> multiSelected = fd.MultiSelected;
+            string path = fd.Path;
 
-        if (canceled)
-        {
-            MessageBox.Query (
-                              "Canceled",
-                              "You canceled navigation and did not pick anything",
-                              "Ok"
-                             );
+            // This needs to be disposed before opening other toplevel
+            fd.Dispose ();
 
-        }
-        else if (_cbAllowMultipleSelection.CheckedState == CheckState.Checked)
-        {
-            MessageBox.Query (
-                              "Chosen!",
-                              "You chose:" + Environment.NewLine + string.Join (Environment.NewLine, multiSelected.Select (m => m)),
-                              "Ok"
-                             );
-        }
-        else
-        {
-            MessageBox.Query (
-                              "Chosen!",
-                              "You chose:" + Environment.NewLine + path,
-                              "Ok"
-                             );
+            if (canceled)
+            {
+                MessageBox.Query (
+                                  "Canceled",
+                                  "You canceled navigation and did not pick anything",
+                                  "Ok"
+                                 );
+            }
+            else if (_cbAllowMultipleSelection.CheckedState == CheckState.Checked)
+            {
+                MessageBox.Query (
+                                  "Chosen!",
+                                  "You chose:" + Environment.NewLine + string.Join (Environment.NewLine, multiSelected.Select (m => m)),
+                                  "Ok"
+                                 );
+            }
+            else
+            {
+                MessageBox.Query (
+                                  "Chosen!",
+                                  "You chose:" + Environment.NewLine + path,
+                                  "Ok"
+                                 );
+            }
         }
     }
 

Examples/UICatalog/Scenarios/GraphViewExample.cs

@@ -144,8 +144,8 @@ public class GraphViewExample : Scenario
             Height = Dim.Fill (1),
             BorderStyle = LineStyle.Single
         };
-        _graphView.Border.Thickness = _thickness;
-        _graphView.Margin.Thickness = _thickness;
+        _graphView.Border!.Thickness = _thickness;
+        _graphView.Margin!.Thickness = _thickness;
         _graphView.Padding.Thickness = _thickness;
 
         app.Add (_graphView);
@@ -955,14 +955,14 @@ public class GraphViewExample : Scenario
         if (_miShowBorder.Checked == true)
         {
             _graphView.BorderStyle = LineStyle.Single;
-            _graphView.Border.Thickness = _thickness;
-            _graphView.Margin.Thickness = _thickness;
+            _graphView.Border!.Thickness = _thickness;
+            _graphView.Margin!.Thickness = _thickness;
             _graphView.Padding.Thickness = _thickness;
         }
         else
         {
             _graphView.BorderStyle = LineStyle.None;
-            _graphView.Margin.Thickness = Thickness.Empty;
+            _graphView.Margin!.Thickness = Thickness.Empty;
             _graphView.Padding.Thickness = Thickness.Empty;
         }
     }
@@ -999,7 +999,7 @@ public class GraphViewExample : Scenario
 
         protected override void DrawBarLine (GraphView graph, Point start, Point end, BarSeriesBar beingDrawn)
         {
-            IConsoleDriver driver = Application.Driver;
+            IDriver driver = Application.Driver;
 
             int x = start.X;
 

Examples/UICatalog/Scenarios/Images.cs

@@ -50,8 +50,8 @@ public class Images : Scenario
     private SixelToRender _fireSixel;
     private int _fireFrameCounter;
     private bool _isDisposed;
-    private RadioGroup _rgPaletteBuilder;
-    private RadioGroup _rgDistanceAlgorithm;
+    private OptionSelector _osPaletteBuilder;
+    private OptionSelector _osDistanceAlgorithm;
     private NumericUpDown _popularityThreshold;
     private SixelToRender _sixelImage;
 
@@ -408,22 +408,22 @@ public class Images : Scenario
             Y = Pos.Bottom (_pxY) + 1
         };
 
-        _rgPaletteBuilder = new ()
+        _osPaletteBuilder = new ()
         {
-            RadioLabels = new []
-            {
+            Labels =
+            [
                 "Popularity",
                 "Median Cut"
-            },
+            ],
             X = Pos.Right (_sixelView) + 2,
             Y = Pos.Bottom (l1),
-            SelectedItem = 1
+            Value = 1
         };
 
         _popularityThreshold = new ()
         {
-            X = Pos.Right (_rgPaletteBuilder) + 1,
-            Y = Pos.Top (_rgPaletteBuilder),
+            X = Pos.Right (_osPaletteBuilder) + 1,
+            Y = Pos.Top (_osPaletteBuilder),
             Value = 8
         };
 
@@ -439,12 +439,12 @@ public class Images : Scenario
             Text = "Color Distance Algorithm",
             Width = Dim.Auto (),
             X = Pos.Right (_sixelView),
-            Y = Pos.Bottom (_rgPaletteBuilder) + 1
+            Y = Pos.Bottom (_osPaletteBuilder) + 1
         };
 
-        _rgDistanceAlgorithm = new ()
+        _osDistanceAlgorithm = new ()
         {
-            RadioLabels = new []
+            Labels = new []
             {
                 "Euclidian",
                 "CIE76"
@@ -458,10 +458,10 @@ public class Images : Scenario
         _sixelSupported.Add (lblPxY);
         _sixelSupported.Add (_pxY);
         _sixelSupported.Add (l1);
-        _sixelSupported.Add (_rgPaletteBuilder);
+        _sixelSupported.Add (_osPaletteBuilder);
 
         _sixelSupported.Add (l2);
-        _sixelSupported.Add (_rgDistanceAlgorithm);
+        _sixelSupported.Add (_osDistanceAlgorithm);
         _sixelSupported.Add (_popularityThreshold);
         _sixelSupported.Add (lblPopThreshold);
 
@@ -470,7 +470,7 @@ public class Images : Scenario
 
     private IPaletteBuilder GetPaletteBuilder ()
     {
-        switch (_rgPaletteBuilder.SelectedItem)
+        switch (_osPaletteBuilder.Value)
         {
             case 0: return new PopularityPaletteWithThreshold (GetDistanceAlgorithm (), _popularityThreshold.Value);
             case 1: return new MedianCutPaletteBuilder (GetDistanceAlgorithm ());
@@ -480,7 +480,7 @@ public class Images : Scenario
 
     private IColorDistance GetDistanceAlgorithm ()
     {
-        switch (_rgDistanceAlgorithm.SelectedItem)
+        switch (_osDistanceAlgorithm.Value)
         {
             case 0: return new EuclideanColorDistance ();
             case 1: return new CIE76ColorDistance ();

Examples/UICatalog/Scenarios/Keys.cs

@@ -158,10 +158,7 @@ public class Keys : Scenario
         appKeyListView.SchemeName = "TopLevel";
         win.Add (onSwallowedListView);
 
-        if (Application.Driver is IConsoleDriverFacade fac)
-        {
-            fac.InputProcessor.AnsiSequenceSwallowed += (s, e) => { swallowedList.Add (e.Replace ("\x1b","Esc")); };
-        }
+        Application.Driver!.InputProcessor.AnsiSequenceSwallowed += (s, e) => { swallowedList.Add (e.Replace ("\x1b", "Esc")); };
 
         Application.KeyDown += (s, a) => KeyDownPressUp (a, "Down");
         Application.KeyUp += (s, a) => KeyDownPressUp (a, "Up");

Examples/UICatalog/Scenarios/LineCanvasExperiment.cs

@@ -130,9 +130,9 @@ public class LineCanvasExperiment : Scenario
         //    //Scheme = Colors.Schemes ["Error"],
         //    SuperViewRendersLineCanvas = true
         //};
-        //marginWindow.Margin.Scheme = Colors.Schemes ["Error"];
-        //marginWindow.Margin.Thickness = new (1);
-        //marginWindow.Border.Thickness = new (1, 2, 1, 1);
+        //marginWindow.Margin!.Scheme = Colors.Schemes ["Error"];
+        //marginWindow.Margin!.Thickness = new (1);
+        //marginWindow.Border!.Thickness = new (1, 2, 1, 1);
 
         //frame1.Add (marginWindow);
 

Examples/UICatalog/Scenarios/LineDrawing.cs

@@ -210,7 +210,7 @@ public class ToolsView : Window
 {
     private Button _addLayerBtn;
     private readonly AttributeView _colors;
-    private RadioGroup _stylePicker;
+    private OptionSelector<LineStyle> _stylePicker;
 
     public Attribute CurrentColor
     {
@@ -236,10 +236,16 @@ public class ToolsView : Window
 
         _stylePicker = new ()
         {
-            X = 0, Y = Pos.Bottom (_colors), RadioLabels = Enum.GetNames (typeof (LineStyle)).ToArray ()
+            X = 0, Y = Pos.Bottom (_colors), AssignHotKeys = true
         };
-        _stylePicker.SelectedItemChanged += (s, a) => { SetStyle?.Invoke ((LineStyle)a.SelectedItem); };
-        _stylePicker.SelectedItem = 1;
+        _stylePicker.ValueChanged += (s, a) =>
+                                     {
+                                         if (a.Value is { })
+                                         {
+                                             SetStyle?.Invoke ((LineStyle)a.Value);
+                                         }
+                                     };
+        _stylePicker.Value = LineStyle.Single;
 
         _addLayerBtn = new () { Text = "New Layer", X = Pos.Center (), Y = Pos.Bottom (_stylePicker) };
 

Examples/UICatalog/Scenarios/Mazing.cs

@@ -129,7 +129,7 @@ public class Mazing : Scenario
             return;
         }
 
-        Point newPos = _m.Player;
+        Point newPos = _m!.Player;
 
         Command? command = e.Context?.Command;
 

Examples/UICatalog/Scenarios/MessageBoxes.cs

@@ -182,18 +182,19 @@ public class MessageBoxes : Scenario
         };
         frame.Add (label);
 
-        var styleRadioGroup = new RadioGroup
+        var styleOptionSelector = new OptionSelector ()
         {
-            X = Pos.Right (label) + 1, 
-            Y = Pos.Top (label), 
-            RadioLabels = ["_Query", "_Error"],
+            X = Pos.Right (label) + 1,
+            Y = Pos.Top (label),
+            Labels = ["_Query", "_Error"],
+            Title = "Sty_le"
         };
-        frame.Add (styleRadioGroup);
+        frame.Add (styleOptionSelector);
 
         label = new ()
         {
             X = 0,
-            Y = Pos.Bottom (styleRadioGroup),
+            Y = Pos.Bottom (styleOptionSelector),
 
             Width = Dim.Width (label),
             Height = 1,
@@ -202,7 +203,7 @@ public class MessageBoxes : Scenario
         };
         var ckbWrapMessage = new CheckBox
         {
-            X = Pos.Right (label) + 1, Y = Pos.Bottom (styleRadioGroup),
+            X = Pos.Right (label) + 1, Y = Pos.Bottom (styleOptionSelector),
             CheckedState = CheckState.Checked,
             Text = "_Wrap Message",
         };
@@ -246,7 +247,7 @@ public class MessageBoxes : Scenario
                                                    btns.Add ($"_{NumberToWords.Convert (i)}");
                                                }
 
-                                               if (styleRadioGroup.SelectedItem == 0)
+                                               if (styleOptionSelector.Value == 0)
                                                {
                                                    buttonPressedLabel.Text =
                                                        $"{MessageBox.Query (

Examples/UICatalog/Scenarios/Navigation.cs

@@ -107,18 +107,7 @@ public class Navigation : Scenario
         //                 };
         //timer.Start ();
 
-        Application.Iteration += (sender, args) =>
-                                 {
-                                     if (progressBar.Fraction == 1.0)
-                                     {
-                                         progressBar.Fraction = 0;
-                                     }
-
-                                     progressBar.Fraction += 0.01f;
-
-                                     Application.Invoke (() => { });
-
-                                 };
+        Application.Iteration += OnApplicationIteration;
 
         View overlappedView2 = CreateOverlappedView (3, 8, 10);
 
@@ -214,12 +203,25 @@ public class Navigation : Scenario
 
         testFrame.SetFocus ();
         Application.Run (app);
+        Application.Iteration -= OnApplicationIteration;
         // timer.Close ();
         app.Dispose ();
         Application.Shutdown ();
 
         return;
 
+        void OnApplicationIteration (object sender, IterationEventArgs args)
+        {
+            if (progressBar.Fraction == 1.0)
+            {
+                progressBar.Fraction = 0;
+            }
+
+            progressBar.Fraction += 0.01f;
+
+            Application.Invoke (() => { });
+        }
+
         void ColorPicker_ColorChanged (object sender, ResultEventArgs<Color> e)
         {
             testFrame.SetScheme (testFrame.GetScheme () with { Normal = new (testFrame.GetAttributeForRole (VisualRole.Normal).Foreground, e.Result) });

Examples/UICatalog/Scenarios/Notepad.cs

@@ -1,6 +1,4 @@
-using System.IO;
-using System.Linq;
-
+#nullable enable
 namespace UICatalog.Scenarios;
 
 [ScenarioMetadata ("Notepad", "Multi-tab text editor using the TabView control.")]
@@ -9,10 +7,10 @@ namespace UICatalog.Scenarios;
 [ScenarioCategory ("TextView")]
 public class Notepad : Scenario
 {
-    private TabView _focusedTabView;
-    public Shortcut LenShortcut { get; private set; }
+    private TabView? _focusedTabView;
     private int _numNewTabs = 1;
-    private TabView _tabView;
+    private TabView? _tabView;
+    public Shortcut? LenShortcut { get; private set; }
 
     public override void Main ()
     {
@@ -67,14 +65,15 @@ public class Notepad : Scenario
         top.Add (_tabView);
         LenShortcut = new (Key.Empty, "Len: ", null);
 
-        var statusBar = new StatusBar (new [] {
-                                           new (Application.QuitKey, $"Quit", Quit),
-                                           new Shortcut(Key.F2, "Open", Open),
-                                           new Shortcut(Key.F1, "New", New),
+        var statusBar = new StatusBar (
+                                       [
+                                           new (Application.QuitKey, "Quit", Quit),
+                                           new (Key.F2, "Open", Open),
+                                           new (Key.F1, "New", New),
                                            new (Key.F3, "Save", Save),
                                            new (Key.F6, "Close", Close),
                                            LenShortcut
-                                       }
+                                       ]
                                       )
         {
             AlignmentModes = AlignmentModes.IgnoreFirstOrLast
@@ -97,7 +96,7 @@ public class Notepad : Scenario
         Application.Shutdown ();
     }
 
-    public void Save () { Save (_focusedTabView, _focusedTabView.SelectedTab); }
+    public void Save () { Save (_focusedTabView!, _focusedTabView!.SelectedTab!); }
 
     public void Save (TabView tabViewToSave, Tab tabToSave)
     {
@@ -119,7 +118,7 @@ public class Notepad : Scenario
 
     public bool SaveAs ()
     {
-        var tab = _focusedTabView.SelectedTab as OpenedFile;
+        var tab = _focusedTabView!.SelectedTab as OpenedFile;
 
         if (tab == null)
         {
@@ -152,7 +151,7 @@ public class Notepad : Scenario
         return true;
     }
 
-    private void Close () { Close (_focusedTabView, _focusedTabView.SelectedTab); }
+    private void Close () { Close (_focusedTabView!, _focusedTabView!.SelectedTab!); }
 
     private void Close (TabView tv, Tab tabToClose)
     {
@@ -196,7 +195,7 @@ public class Notepad : Scenario
 
         // close and dispose the tab
         tv.RemoveTab (tab);
-        tab.View.Dispose ();
+        tab.View?.Dispose ();
         _focusedTabView = tv;
 
         // If last tab is closed, open a new one
@@ -217,7 +216,7 @@ public class Notepad : Scenario
         return tv;
     }
 
-    private void New () { Open (null, $"new {_numNewTabs++}"); }
+    private void New () { Open (null!, $"new {_numNewTabs++}"); }
 
     private void Open ()
     {
@@ -246,26 +245,27 @@ public class Notepad : Scenario
 
     /// <summary>Creates a new tab with initial text</summary>
     /// <param name="fileInfo">File that was read or null if a new blank document</param>
+    /// <param name="tabName"></param>
     private void Open (FileInfo fileInfo, string tabName)
     {
         var tab = new OpenedFile (this) { DisplayText = tabName, File = fileInfo };
         tab.View = tab.CreateTextView (fileInfo);
         tab.SavedText = tab.View.Text;
-        tab.RegisterTextViewEvents (_focusedTabView);
+        tab.RegisterTextViewEvents (_focusedTabView!);
 
-        _focusedTabView.AddTab (tab, true);
+        _focusedTabView!.AddTab (tab, true);
     }
 
     private void Quit () { Application.RequestStop (); }
 
-    private void TabView_SelectedTabChanged (object sender, TabChangedEventArgs e)
+    private void TabView_SelectedTabChanged (object? sender, TabChangedEventArgs e)
     {
-        LenShortcut.Title = $"Len:{e.NewTab?.View?.Text?.Length ?? 0}";
+        LenShortcut!.Title = $"Len:{e.NewTab?.View?.Text?.Length ?? 0}";
 
         e.NewTab?.View?.SetFocus ();
     }
 
-    private void TabView_TabClicked (object sender, TabMouseEventArgs e)
+    private void TabView_TabClicked (object? sender, TabMouseEventArgs e)
     {
         // we are only interested in right clicks
         if (!e.MouseEvent.Flags.HasFlag (MouseFlags.Button3Clicked))
@@ -281,12 +281,12 @@ public class Notepad : Scenario
         }
         else
         {
-            var tv = (TabView)sender;
+            var tv = (TabView)sender!;
             var t = (OpenedFile)e.Tab;
 
             items =
             [
-                new MenuItemv2 ("Save", "", () => Save (_focusedTabView, e.Tab)),
+                new MenuItemv2 ("Save", "", () => Save (_focusedTabView!, e.Tab)),
                 new MenuItemv2 ("Close", "", () => Close (tv, e.Tab))
             ];
 
@@ -303,12 +303,12 @@ public class Notepad : Scenario
 
     private class OpenedFile (Notepad notepad) : Tab
     {
-        private Notepad _notepad = notepad;
+        private readonly Notepad _notepad = notepad;
 
         public OpenedFile CloneTo (TabView other)
         {
             var newTab = new OpenedFile (_notepad) { DisplayText = base.Text, File = File };
-            newTab.View = newTab.CreateTextView (newTab.File);
+            newTab.View = newTab.CreateTextView (newTab.File!);
             newTab.SavedText = newTab.View.Text;
             newTab.RegisterTextViewEvents (other);
             other.AddTab (newTab, true);
@@ -316,11 +316,11 @@ public class Notepad : Scenario
             return newTab;
         }
 
-        public View CreateTextView (FileInfo file)
+        public View CreateTextView (FileInfo? file)
         {
             var initialText = string.Empty;
 
-            if (file != null && file.Exists)
+            if (file is { Exists: true })
             {
                 initialText = System.IO.File.ReadAllText (file.FullName);
             }
@@ -336,11 +336,11 @@ public class Notepad : Scenario
             };
         }
 
-        public FileInfo File { get; set; }
+        public FileInfo? File { get; set; }
 
         public void RegisterTextViewEvents (TabView parent)
         {
-            var textView = (TextView)View;
+            var textView = (TextView)View!;
 
             // when user makes changes rename tab to indicate unsaved
             textView.ContentsChanged += (s, k) =>
@@ -362,19 +362,20 @@ public class Notepad : Scenario
                                                     DisplayText = Text.TrimEnd ('*');
                                                 }
                                             }
-                                            _notepad.LenShortcut.Title = $"Len:{textView.Text.Length}";
+
+                                            _notepad.LenShortcut!.Title = $"Len:{textView.Text.Length}";
                                         };
         }
 
         /// <summary>The text of the tab the last time it was saved</summary>
         /// <value></value>
-        public string SavedText { get; set; }
+        public string? SavedText { get; set; }
 
-        public bool UnsavedChanges => !string.Equals (SavedText, View.Text);
+        public bool UnsavedChanges => !string.Equals (SavedText, View!.Text);
 
         internal void Save ()
         {
-            string newText = View.Text;
+            string newText = View!.Text;
 
             if (File is null || string.IsNullOrWhiteSpace (File.FullName))
             {

Examples/UICatalog/Scenarios/NumericUpDownDemo.cs

@@ -266,14 +266,14 @@ internal class NumericUpDownEditor<T> : View where T : notnull
 
             void NumericUpDownOnIncrementChanged (object? o, EventArgs<T> eventArgs)
             {
-                _increment.Text = _numericUpDown.Increment.ToString ();
+                _increment.Text = _numericUpDown!.Increment?.ToString ();
             }
 
             Add (_numericUpDown);
 
             _value.Text = _numericUpDown.Text;
             _format.Text = _numericUpDown.Format;
-            _increment.Text = _numericUpDown.Increment.ToString ();
+            _increment.Text = _numericUpDown!.Increment?.ToString ();
         }
     }
 

Examples/UICatalog/Scenarios/PosAlignDemo.cs

@@ -1,14 +1,10 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-
 namespace UICatalog.Scenarios;
 
 [ScenarioMetadata ("Pos.Align", "Demonstrates Pos.Align")]
 [ScenarioCategory ("Layout")]
 public sealed class PosAlignDemo : Scenario
 {
-    private readonly Aligner _horizAligner = new () { AlignmentModes = AlignmentModes.StartToEnd | AlignmentModes.AddSpaceBetweenItems};
+    private readonly Aligner _horizAligner = new () { AlignmentModes = AlignmentModes.StartToEnd | AlignmentModes.AddSpaceBetweenItems };
     private int _leftMargin;
     private readonly Aligner _vertAligner = new () { AlignmentModes = AlignmentModes.StartToEnd | AlignmentModes.AddSpaceBetweenItems };
     private int _topMargin;
@@ -40,43 +36,42 @@ public sealed class PosAlignDemo : Scenario
 
     private void SetupControls (Window appWindow, Dimension dimension, Schemes scheme)
     {
-        RadioGroup alignRadioGroup = new ()
+        OptionSelector<Alignment> alignOptionSelector = new ()
         {
-            RadioLabels = Enum.GetNames<Alignment> (),
-            SchemeName = SchemeManager.SchemesToSchemeName (scheme),
+            SchemeName = SchemeManager.SchemesToSchemeName (scheme)
         };
 
         if (dimension == Dimension.Width)
         {
-            alignRadioGroup.X = Pos.Align (_horizAligner.Alignment);
-            alignRadioGroup.Y = Pos.Center ();
+            alignOptionSelector.X = Pos.Align (_horizAligner.Alignment);
+            alignOptionSelector.Y = Pos.Center ();
         }
         else
         {
-            alignRadioGroup.X = Pos.Center ();
-            alignRadioGroup.Y = Pos.Align (_vertAligner.Alignment);
+            alignOptionSelector.X = Pos.Center ();
+            alignOptionSelector.Y = Pos.Align (_vertAligner.Alignment);
         }
 
-        alignRadioGroup.SelectedItemChanged += (s, e) =>
-                                               {
-                                                   if (dimension == Dimension.Width)
-                                                   {
-                                                       _horizAligner.Alignment =
-                                                           (Alignment)Enum.Parse (
-                                                                                  typeof (Alignment),
-                                                                                  alignRadioGroup.RadioLabels [alignRadioGroup.SelectedItem]);
-                                                       UpdatePosAlignObjects (appWindow, dimension, _horizAligner);
-                                                   }
-                                                   else
-                                                   {
-                                                       _vertAligner.Alignment =
-                                                           (Alignment)Enum.Parse (
-                                                                                  typeof (Alignment),
-                                                                                  alignRadioGroup.RadioLabels [alignRadioGroup.SelectedItem]);
-                                                       UpdatePosAlignObjects (appWindow, dimension, _vertAligner);
-                                                   }
-                                               };
-        appWindow.Add (alignRadioGroup);
+        alignOptionSelector.ValueChanged += (s, e) =>
+                                            {
+                                                if (alignOptionSelector.Value is null)
+                                                {
+                                                    return;
+                                                }
+
+                                                if (dimension == Dimension.Width)
+                                                {
+                                                    _horizAligner.Alignment = alignOptionSelector.Value.Value;
+
+                                                    UpdatePosAlignObjects (appWindow, dimension, _horizAligner);
+                                                }
+                                                else
+                                                {
+                                                    _vertAligner.Alignment = alignOptionSelector.Value.Value;
+                                                    UpdatePosAlignObjects (appWindow, dimension, _vertAligner);
+                                                }
+                                            };
+        appWindow.Add (alignOptionSelector);
 
         CheckBox endToStartCheckBox = new ()
         {
@@ -88,32 +83,32 @@ public sealed class PosAlignDemo : Scenario
         {
             endToStartCheckBox.CheckedState = _horizAligner.AlignmentModes.HasFlag (AlignmentModes.EndToStart) ? CheckState.Checked : CheckState.UnChecked;
             endToStartCheckBox.X = Pos.Align (_horizAligner.Alignment);
-            endToStartCheckBox.Y = Pos.Top (alignRadioGroup);
+            endToStartCheckBox.Y = Pos.Top (alignOptionSelector);
         }
         else
         {
             endToStartCheckBox.CheckedState = _vertAligner.AlignmentModes.HasFlag (AlignmentModes.EndToStart) ? CheckState.Checked : CheckState.UnChecked;
-            endToStartCheckBox.X = Pos.Left (alignRadioGroup);
+            endToStartCheckBox.X = Pos.Left (alignOptionSelector);
             endToStartCheckBox.Y = Pos.Align (_vertAligner.Alignment);
         }
 
         endToStartCheckBox.CheckedStateChanging += (s, e) =>
-                                      {
-                                          if (dimension == Dimension.Width)
-                                          {
-                                              _horizAligner.AlignmentModes = e.Result == CheckState.Checked
-                                                                                 ? _horizAligner.AlignmentModes | AlignmentModes.EndToStart
-                                                                                 : _horizAligner.AlignmentModes & ~AlignmentModes.EndToStart;
-                                              UpdatePosAlignObjects (appWindow, dimension, _horizAligner);
-                                          }
-                                          else
-                                          {
-                                              _vertAligner.AlignmentModes = e.Result == CheckState.Checked
-                                                                                ? _vertAligner.AlignmentModes | AlignmentModes.EndToStart
-                                                                                : _vertAligner.AlignmentModes & ~AlignmentModes.EndToStart;
-                                              UpdatePosAlignObjects (appWindow, dimension, _vertAligner);
-                                          }
-                                      };
+                                                   {
+                                                       if (dimension == Dimension.Width)
+                                                       {
+                                                           _horizAligner.AlignmentModes = e.Result == CheckState.Checked
+                                                                                              ? _horizAligner.AlignmentModes | AlignmentModes.EndToStart
+                                                                                              : _horizAligner.AlignmentModes & ~AlignmentModes.EndToStart;
+                                                           UpdatePosAlignObjects (appWindow, dimension, _horizAligner);
+                                                       }
+                                                       else
+                                                       {
+                                                           _vertAligner.AlignmentModes = e.Result == CheckState.Checked
+                                                                                             ? _vertAligner.AlignmentModes | AlignmentModes.EndToStart
+                                                                                             : _vertAligner.AlignmentModes & ~AlignmentModes.EndToStart;
+                                                           UpdatePosAlignObjects (appWindow, dimension, _vertAligner);
+                                                       }
+                                                   };
         appWindow.Add (endToStartCheckBox);
 
         CheckBox ignoreFirstOrLast = new ()
@@ -124,34 +119,35 @@ public sealed class PosAlignDemo : Scenario
 
         if (dimension == Dimension.Width)
         {
-            ignoreFirstOrLast.CheckedState = _horizAligner.AlignmentModes.HasFlag (AlignmentModes.IgnoreFirstOrLast) ? CheckState.Checked : CheckState.UnChecked;
+            ignoreFirstOrLast.CheckedState =
+                _horizAligner.AlignmentModes.HasFlag (AlignmentModes.IgnoreFirstOrLast) ? CheckState.Checked : CheckState.UnChecked;
             ignoreFirstOrLast.X = Pos.Align (_horizAligner.Alignment);
-            ignoreFirstOrLast.Y = Pos.Top (alignRadioGroup);
+            ignoreFirstOrLast.Y = Pos.Top (alignOptionSelector);
         }
         else
         {
             ignoreFirstOrLast.CheckedState = _vertAligner.AlignmentModes.HasFlag (AlignmentModes.IgnoreFirstOrLast) ? CheckState.Checked : CheckState.UnChecked;
-            ignoreFirstOrLast.X = Pos.Left (alignRadioGroup);
+            ignoreFirstOrLast.X = Pos.Left (alignOptionSelector);
             ignoreFirstOrLast.Y = Pos.Align (_vertAligner.Alignment);
         }
 
         ignoreFirstOrLast.CheckedStateChanging += (s, e) =>
-                                     {
-                                         if (dimension == Dimension.Width)
-                                         {
-                                             _horizAligner.AlignmentModes = e.Result == CheckState.Checked
-                                                     ? _horizAligner.AlignmentModes | AlignmentModes.IgnoreFirstOrLast
-                                                     : _horizAligner.AlignmentModes & ~AlignmentModes.IgnoreFirstOrLast;
-                                             UpdatePosAlignObjects (appWindow, dimension, _horizAligner);
-                                         }
-                                         else
-                                         {
-                                             _vertAligner.AlignmentModes = e.Result == CheckState.Checked
-                                                                               ? _vertAligner.AlignmentModes | AlignmentModes.IgnoreFirstOrLast
-                                                                               : _vertAligner.AlignmentModes & ~AlignmentModes.IgnoreFirstOrLast;
-                                             UpdatePosAlignObjects (appWindow, dimension, _vertAligner);
-                                         }
-                                     };
+                                                  {
+                                                      if (dimension == Dimension.Width)
+                                                      {
+                                                          _horizAligner.AlignmentModes = e.Result == CheckState.Checked
+                                                                                             ? _horizAligner.AlignmentModes | AlignmentModes.IgnoreFirstOrLast
+                                                                                             : _horizAligner.AlignmentModes & ~AlignmentModes.IgnoreFirstOrLast;
+                                                          UpdatePosAlignObjects (appWindow, dimension, _horizAligner);
+                                                      }
+                                                      else
+                                                      {
+                                                          _vertAligner.AlignmentModes = e.Result == CheckState.Checked
+                                                                                            ? _vertAligner.AlignmentModes | AlignmentModes.IgnoreFirstOrLast
+                                                                                            : _vertAligner.AlignmentModes & ~AlignmentModes.IgnoreFirstOrLast;
+                                                          UpdatePosAlignObjects (appWindow, dimension, _vertAligner);
+                                                      }
+                                                  };
         appWindow.Add (ignoreFirstOrLast);
 
         CheckBox addSpacesBetweenItems = new ()
@@ -162,34 +158,40 @@ public sealed class PosAlignDemo : Scenario
 
         if (dimension == Dimension.Width)
         {
-            addSpacesBetweenItems.CheckedState = _horizAligner.AlignmentModes.HasFlag (AlignmentModes.AddSpaceBetweenItems) ? CheckState.Checked : CheckState.UnChecked;
+            addSpacesBetweenItems.CheckedState =
+                _horizAligner.AlignmentModes.HasFlag (AlignmentModes.AddSpaceBetweenItems) ? CheckState.Checked : CheckState.UnChecked;
             addSpacesBetweenItems.X = Pos.Align (_horizAligner.Alignment);
-            addSpacesBetweenItems.Y = Pos.Top (alignRadioGroup);
+            addSpacesBetweenItems.Y = Pos.Top (alignOptionSelector);
         }
         else
         {
-            addSpacesBetweenItems.CheckedState = _vertAligner.AlignmentModes.HasFlag (AlignmentModes.AddSpaceBetweenItems) ? CheckState.Checked : CheckState.UnChecked;
-            addSpacesBetweenItems.X = Pos.Left (alignRadioGroup);
+            addSpacesBetweenItems.CheckedState =
+                _vertAligner.AlignmentModes.HasFlag (AlignmentModes.AddSpaceBetweenItems) ? CheckState.Checked : CheckState.UnChecked;
+            addSpacesBetweenItems.X = Pos.Left (alignOptionSelector);
             addSpacesBetweenItems.Y = Pos.Align (_vertAligner.Alignment);
         }
 
         addSpacesBetweenItems.CheckedStateChanging += (s, e) =>
-                                         {
-                                             if (dimension == Dimension.Width)
-                                             {
-                                                 _horizAligner.AlignmentModes = e.Result == CheckState.Checked
-                                                                                    ? _horizAligner.AlignmentModes | AlignmentModes.AddSpaceBetweenItems
-                                                                                    : _horizAligner.AlignmentModes & ~AlignmentModes.AddSpaceBetweenItems;
-                                                 UpdatePosAlignObjects (appWindow, dimension, _horizAligner);
-                                             }
-                                             else
-                                             {
-                                                 _vertAligner.AlignmentModes = e.Result == CheckState.Checked
-                                                                                   ? _vertAligner.AlignmentModes | AlignmentModes.AddSpaceBetweenItems
-                                                                                   : _vertAligner.AlignmentModes & ~AlignmentModes.AddSpaceBetweenItems;
-                                                 UpdatePosAlignObjects (appWindow, dimension, _vertAligner);
-                                             }
-                                         };
+                                                      {
+                                                          if (dimension == Dimension.Width)
+                                                          {
+                                                              _horizAligner.AlignmentModes = e.Result == CheckState.Checked
+                                                                                                 ? _horizAligner.AlignmentModes
+                                                                                                   | AlignmentModes.AddSpaceBetweenItems
+                                                                                                 : _horizAligner.AlignmentModes
+                                                                                                   & ~AlignmentModes.AddSpaceBetweenItems;
+                                                              UpdatePosAlignObjects (appWindow, dimension, _horizAligner);
+                                                          }
+                                                          else
+                                                          {
+                                                              _vertAligner.AlignmentModes = e.Result == CheckState.Checked
+                                                                                                ? _vertAligner.AlignmentModes
+                                                                                                  | AlignmentModes.AddSpaceBetweenItems
+                                                                                                : _vertAligner.AlignmentModes
+                                                                                                  & ~AlignmentModes.AddSpaceBetweenItems;
+                                                              UpdatePosAlignObjects (appWindow, dimension, _vertAligner);
+                                                          }
+                                                      };
 
         appWindow.Add (addSpacesBetweenItems);
 
@@ -202,7 +204,7 @@ public sealed class PosAlignDemo : Scenario
         if (dimension == Dimension.Width)
         {
             margin.X = Pos.Align (_horizAligner.Alignment);
-            margin.Y = Pos.Top (alignRadioGroup);
+            margin.Y = Pos.Top (alignOptionSelector);
         }
         else
         {
@@ -211,31 +213,31 @@ public sealed class PosAlignDemo : Scenario
         }
 
         margin.CheckedStateChanging += (s, e) =>
-                          {
-                              if (dimension == Dimension.Width)
-                              {
-                                  _leftMargin = e.Result == CheckState.Checked ? 1 : 0;
-                                  UpdatePosAlignObjects (appWindow, dimension, _horizAligner);
-                              }
-                              else
-                              {
-                                  _topMargin = e.Result == CheckState.Checked ? 1 : 0;
-                                  UpdatePosAlignObjects (appWindow, dimension, _vertAligner);
-                              }
-                          };
+                                       {
+                                           if (dimension == Dimension.Width)
+                                           {
+                                               _leftMargin = e.Result == CheckState.Checked ? 1 : 0;
+                                               UpdatePosAlignObjects (appWindow, dimension, _horizAligner);
+                                           }
+                                           else
+                                           {
+                                               _topMargin = e.Result == CheckState.Checked ? 1 : 0;
+                                               UpdatePosAlignObjects (appWindow, dimension, _vertAligner);
+                                           }
+                                       };
         appWindow.Add (margin);
 
         List<Button> addedViews =
         [
             new ()
             {
-                X = dimension == Dimension.Width ? Pos.Align (_horizAligner.Alignment) : Pos.Left (alignRadioGroup),
-                Y = dimension == Dimension.Width ? Pos.Top (alignRadioGroup) : Pos.Align (_vertAligner.Alignment),
+                X = dimension == Dimension.Width ? Pos.Align (_horizAligner.Alignment) : Pos.Left (alignOptionSelector),
+                Y = dimension == Dimension.Width ? Pos.Top (alignOptionSelector) : Pos.Align (_vertAligner.Alignment),
                 Text = NumberToWords.Convert (0)
             }
         ];
 
-        NumericUpDown<int> addedViewsUpDown = new()
+        NumericUpDown<int> addedViewsUpDown = new ()
         {
             Width = 9,
             Title = "Added",
@@ -247,14 +249,14 @@ public sealed class PosAlignDemo : Scenario
         if (dimension == Dimension.Width)
         {
             addedViewsUpDown.X = Pos.Align (_horizAligner.Alignment);
-            addedViewsUpDown.Y = Pos.Top (alignRadioGroup);
-            addedViewsUpDown.Border.Thickness = new (0, 1, 0, 0);
+            addedViewsUpDown.Y = Pos.Top (alignOptionSelector);
+            addedViewsUpDown.Border!.Thickness = new (0, 1, 0, 0);
         }
         else
         {
-            addedViewsUpDown.X = Pos.Left (alignRadioGroup);
+            addedViewsUpDown.X = Pos.Left (alignOptionSelector);
             addedViewsUpDown.Y = Pos.Align (_vertAligner.Alignment);
-            addedViewsUpDown.Border.Thickness = new (1, 0, 0, 0);
+            addedViewsUpDown.Border!.Thickness = new (1, 0, 0, 0);
         }
 
         addedViewsUpDown.ValueChanging += (s, e) =>
@@ -286,8 +288,10 @@ public sealed class PosAlignDemo : Scenario
                                                   {
                                                       var button = new Button
                                                       {
-                                                          X = dimension == Dimension.Width ? Pos.Align (_horizAligner.Alignment) : Pos.Left (alignRadioGroup),
-                                                          Y = dimension == Dimension.Width ? Pos.Top (alignRadioGroup) : Pos.Align (_vertAligner.Alignment),
+                                                          X = dimension == Dimension.Width
+                                                                  ? Pos.Align (_horizAligner.Alignment)
+                                                                  : Pos.Left (alignOptionSelector),
+                                                          Y = dimension == Dimension.Width ? Pos.Top (alignOptionSelector) : Pos.Align (_vertAligner.Alignment),
                                                           Text = NumberToWords.Convert (i + 1)
                                                       };
                                                       appWindow.Add (button);
@@ -319,7 +323,7 @@ public sealed class PosAlignDemo : Scenario
                                         aligner.Alignment,
                                         aligner.AlignmentModes,
                                         posAlign!.GroupId);
-                    view.Margin.Thickness = new (_leftMargin, view.Margin.Thickness.Top, view.Margin.Thickness.Right, view.Margin.Thickness.Bottom);
+                    view.Margin!.Thickness = new (_leftMargin, view.Margin!.Thickness.Top, view.Margin!.Thickness.Right, view.Margin!.Thickness.Bottom);
                 }
                 else
                 {
@@ -330,7 +334,7 @@ public sealed class PosAlignDemo : Scenario
                                         aligner.AlignmentModes,
                                         posAlign!.GroupId);
 
-                    view.Margin.Thickness = new (view.Margin.Thickness.Left, _topMargin, view.Margin.Thickness.Right, view.Margin.Thickness.Bottom);
+                    view.Margin!.Thickness = new (view.Margin!.Thickness.Left, _topMargin, view.Margin!.Thickness.Right, view.Margin!.Thickness.Bottom);
                 }
             }
         }
@@ -351,46 +355,48 @@ public sealed class PosAlignDemo : Scenario
             Width = Dim.Percent (40),
             Height = Dim.Percent (40)
         };
-        container.Padding.Thickness = new (8, 1, 0, 0);
+        container.Padding!.Thickness = new (8, 1, 0, 0);
         container.Padding.SchemeName = "Error";
 
         Aligner widthAligner = new () { AlignmentModes = AlignmentModes.StartToEnd };
 
-        RadioGroup widthAlignRadioGroup = new ()
+        OptionSelector widthAlignOptionSelector = new ()
         {
-            RadioLabels = Enum.GetNames<Alignment> (),
+            Labels = Enum.GetNames<Alignment> (),
             Orientation = Orientation.Horizontal,
             X = Pos.Center ()
         };
-        container.Padding.Add (widthAlignRadioGroup);
-
-        widthAlignRadioGroup.SelectedItemChanged += (sender, e) =>
-                                                    {
-                                                        widthAligner.Alignment =
-                                                            (Alignment)Enum.Parse (
-                                                                                   typeof (Alignment),
-                                                                                   widthAlignRadioGroup.RadioLabels [widthAlignRadioGroup.SelectedItem]);
-                                                        UpdatePosAlignObjects (container, Dimension.Width, widthAligner);
-                                                    };
+        container.Padding.Add (widthAlignOptionSelector);
+
+        widthAlignOptionSelector.ValueChanged += (_, _) =>
+                                                        {
+                                                            widthAligner.Alignment =
+                                                                (Alignment)Enum.Parse (
+                                                                                       typeof (Alignment),
+                                                                                       widthAlignOptionSelector.Labels [widthAlignOptionSelector
+                                                                                           .Value!.Value]);
+                                                            UpdatePosAlignObjects (container, Dimension.Width, widthAligner);
+                                                        };
 
         Aligner heightAligner = new () { AlignmentModes = AlignmentModes.StartToEnd };
 
-        RadioGroup heightAlignRadioGroup = new ()
+        OptionSelector heightAlignOptionSelector = new ()
         {
-            RadioLabels = Enum.GetNames<Alignment> (),
+            Labels = Enum.GetNames<Alignment> (),
             Orientation = Orientation.Vertical,
             Y = Pos.Center ()
         };
-        container.Padding.Add (heightAlignRadioGroup);
-
-        heightAlignRadioGroup.SelectedItemChanged += (sender, e) =>
-                                                     {
-                                                         heightAligner.Alignment =
-                                                             (Alignment)Enum.Parse (
-                                                                                    typeof (Alignment),
-                                                                                    heightAlignRadioGroup.RadioLabels [heightAlignRadioGroup.SelectedItem]);
-                                                         UpdatePosAlignObjects (container, Dimension.Height, heightAligner);
-                                                     };
+        container.Padding.Add (heightAlignOptionSelector);
+
+        heightAlignOptionSelector.ValueChanged += (sender, e) =>
+                                                         {
+                                                             heightAligner.Alignment =
+                                                                 (Alignment)Enum.Parse (
+                                                                                        typeof (Alignment),
+                                                                                        heightAlignOptionSelector.Labels [heightAlignOptionSelector
+                                                                                            .Value!.Value]);
+                                                             UpdatePosAlignObjects (container, Dimension.Height, heightAligner);
+                                                         };
 
         for (var i = 0; i < 9; i++)
 
@@ -401,7 +407,7 @@ public sealed class PosAlignDemo : Scenario
                 Text = $"{i}",
                 BorderStyle = LineStyle.Dashed,
                 Height = Dim.Auto (),
-                Width = Dim.Auto() + 2
+                Width = Dim.Auto () + 2
             };
 
             v.X = Pos.Align (widthAligner.Alignment, widthAligner.AlignmentModes, i / 3);

Examples/UICatalog/Scenarios/ProgressBarStyles.cs

@@ -132,15 +132,15 @@ public class ProgressBarStyles : Scenario
         List<ProgressBarFormat> pbFormatEnum =
             Enum.GetValues (typeof (ProgressBarFormat)).Cast<ProgressBarFormat> ().ToList ();
 
-        var rbPBFormat = new RadioGroup
+        OptionSelector<ProgressBarFormat> osPbFormat = new ()
         {
             BorderStyle = LineStyle.Single,
             Title = "ProgressBarFormat",
             X = Pos.Center (),
             Y = Pos.Align (Alignment.Start),
-            RadioLabels = pbFormatEnum.Select (e => e.ToString ()).ToArray ()
+            AssignHotKeys = true
         };
-        container.Add (rbPBFormat);
+        container.Add (osPbFormat);
 
         var button = new Button
         {
@@ -161,7 +161,7 @@ public class ProgressBarStyles : Scenario
         };
         container.Add (blocksPB);
 
-        rbPBFormat.SelectedItem = (int)blocksPB.ProgressBarFormat;
+        osPbFormat.Value = blocksPB.ProgressBarFormat;
 
         var continuousPB = new ProgressBar
         {
@@ -256,13 +256,19 @@ public class ProgressBarStyles : Scenario
                                       };
 
 
-        rbPBFormat.SelectedItemChanged += (s, e) =>
-                                          {
-                                              blocksPB.ProgressBarFormat = (ProgressBarFormat)e.SelectedItem;
-                                              continuousPB.ProgressBarFormat = (ProgressBarFormat)e.SelectedItem;
-                                              marqueesBlocksPB.ProgressBarFormat = (ProgressBarFormat)e.SelectedItem;
-                                              marqueesContinuousPB.ProgressBarFormat = (ProgressBarFormat)e.SelectedItem;
-                                          };
+        osPbFormat.ValueChanged += (s, e) =>
+                                   {
+                                       if (e.Value is null)
+                                       {
+                                           return;
+                                       }
+
+                                       blocksPB.ProgressBarFormat = e.Value.Value;
+                                       continuousPB.ProgressBarFormat = e.Value.Value;
+                                       marqueesBlocksPB.ProgressBarFormat = e.Value.Value;
+                                       marqueesContinuousPB.ProgressBarFormat = e.Value.Value;
+
+                                   };
 
         ckbBidirectional.CheckedStateChanging += (s, e) =>
                                    {

Examples/UICatalog/Scenarios/RegionScenario.cs

@@ -1,7 +1,4 @@
 #nullable enable
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using UICatalog;
 using UICatalog.Scenarios;
@@ -40,7 +37,7 @@ public class RegionScenario : Scenario
 
         tools.SetStyle += b =>
                           {
-                              _drawStyle = (RegionDrawStyles)b;
+                              _drawStyle = b;
                               app.SetNeedsDraw ();
                           };
 
@@ -169,8 +166,8 @@ public class ToolsView : Window
 {
     //private Button _addLayerBtn;
     private readonly AttributeView _attributeView = new ();
-    private RadioGroup? _stylePicker;
-    private RegionOpSelector? _regionOpSelector;
+    private OptionSelector<RegionDrawStyles>? _stylePicker;
+    private OptionSelector<RegionOp>? _regionOpSelector;
 
     public Attribute? CurrentAttribute
     {
@@ -197,22 +194,30 @@ public class ToolsView : Window
         _stylePicker = new ()
         {
             Width = Dim.Fill (),
-            X = 0, Y = Pos.Bottom (_attributeView) + 1, RadioLabels = Enum.GetNames<RegionDrawStyles> ().Select (n => n = "_" + n).ToArray ()
+            X = 0, Y = Pos.Bottom (_attributeView) + 1,
+            AssignHotKeys = true
         };
         _stylePicker.BorderStyle = LineStyle.Single;
         _stylePicker.Border!.Thickness = new (0, 1, 0, 0);
         _stylePicker.Title = "Draw Style";
 
-        _stylePicker.SelectedItemChanged += (s, a) => { SetStyle?.Invoke ((LineStyle)a.SelectedItem!); };
-        _stylePicker.SelectedItem = (int)RegionDrawStyles.FillOnly;
+        _stylePicker.ValueChanged += (s, a) => { SetStyle?.Invoke ((RegionDrawStyles)a.Value!); };
+        _stylePicker.Value = RegionDrawStyles.FillOnly;
 
         _regionOpSelector = new ()
         {
             X = 0,
-            Y = Pos.Bottom (_stylePicker) + 1
+            Y = Pos.Bottom (_stylePicker) + 1,
+            AssignHotKeys = true
         };
-        _regionOpSelector.SelectedItemChanged += (s, a) => { RegionOpChanged?.Invoke (this, a); };
-        _regionOpSelector.SelectedItem = RegionOp.MinimalUnion;
+        _regionOpSelector.ValueChanged += (s, a) =>
+                                          {
+                                              if (a.Value is { })
+                                              {
+                                                  RegionOpChanged?.Invoke (this, (RegionOp)a.Value);
+                                              }
+                                          };
+        _regionOpSelector.Value = RegionOp.MinimalUnion;
 
         //_addLayerBtn = new () { Text = "New Layer", X = Pos.Center (), Y = Pos.Bottom (_stylePicker) };
 
@@ -222,39 +227,7 @@ public class ToolsView : Window
 
     public event EventHandler<Attribute?>? AttributeChanged;
     public event EventHandler<RegionOp>? RegionOpChanged;
-    public event Action<LineStyle>? SetStyle;
-}
-
-public class RegionOpSelector : View
-{
-    private readonly RadioGroup _radioGroup;
-
-    public RegionOpSelector ()
-    {
-        Width = Dim.Auto ();
-        Height = Dim.Auto ();
-
-        BorderStyle = LineStyle.Single;
-        Border!.Thickness = new (0, 1, 0, 0);
-        Title = "RegionOp";
-
-        _radioGroup = new ()
-        {
-            X = 0,
-            Y = 0,
-            RadioLabels = Enum.GetNames<RegionOp> ().Select (n => n = "_" + n).ToArray ()
-        };
-        _radioGroup.SelectedItemChanged += (s, a) => { SelectedItemChanged?.Invoke (this, (RegionOp)a.SelectedItem!); };
-        Add (_radioGroup);
-    }
-
-    public event EventHandler<RegionOp>? SelectedItemChanged;
-
-    public RegionOp SelectedItem
-    {
-        get => (RegionOp)_radioGroup.SelectedItem;
-        set => _radioGroup.SelectedItem = (int)value;
-    }
+    public event Action<RegionDrawStyles>? SetStyle;
 }
 
 public class AttributeView : View

Examples/UICatalog/Scenarios/ScrollBarDemo.cs

@@ -118,23 +118,19 @@ public class ScrollBarDemo : Scenario
         };
         demoFrame.Add (lblOrientationLabel);
 
-        var rgOrientation = new RadioGroup
+        OptionSelector<Orientation> osOrientation = new ()
         {
             X = Pos.Right (lblOrientationLabel) + 1,
             Y = Pos.Top (lblOrientationLabel),
-            RadioLabels = ["Vertical", "Horizontal"],
+            AssignHotKeys = true,
             Orientation = Orientation.Horizontal
         };
-        demoFrame.Add (rgOrientation);
+        demoFrame.Add (osOrientation);
 
-        rgOrientation.SelectedItemChanged += (s, e) =>
+        osOrientation.ValueChanged += (s, e) =>
                                              {
-                                                 if (e.SelectedItem == e.PreviousSelectedItem)
-                                                 {
-                                                     return;
-                                                 }
 
-                                                 if (rgOrientation.SelectedItem == 0)
+                                                 if (osOrientation.Value == Orientation.Horizontal)
                                                  {
                                                      scrollBar.Orientation = Orientation.Vertical;
                                                      scrollBar.X = Pos.AnchorEnd () - 5;

Examples/UICatalog/Scenarios/Selectors.cs

@@ -0,0 +1,287 @@
+#nullable enable
+
+namespace UICatalog.Scenarios;
+
+[ScenarioMetadata ("Selectors", "Demonstrates OptionSelector and FlagSelector.")]
+[ScenarioCategory ("Controls")]
+public sealed class Selectors : Scenario
+{
+    public override void Main ()
+    {
+        // Init
+        Application.Init ();
+
+        // Setup - Create a top-level application window and configure it.
+        Window appWindow = new ()
+        {
+            Title = GetQuitKeyAndName (),
+            BorderStyle = LineStyle.None
+        };
+
+        FrameView? optionSelectorsFrame = null;
+        FrameView? flagSelectorsFrame = null;
+
+        OptionSelector<Orientation> orientationSelector = new ()
+        {
+            Orientation = Orientation.Horizontal,
+            BorderStyle = LineStyle.Dotted,
+            Title = "Selector Or_ientation",
+            Value = Orientation.Vertical
+        };
+        orientationSelector.ValueChanged += OrientationSelectorOnSelectedItemChanged;
+
+        FlagSelector<SelectorStyles> stylesSelector = new ()
+        {
+            X = Pos.Right (orientationSelector) + 1,
+            Orientation = Orientation.Horizontal,
+            BorderStyle = LineStyle.Dotted,
+            Title = "Selector St_yles",
+        };
+        stylesSelector.ValueChanged += StylesSelectorOnValueChanged;
+
+        NumericUpDown<int> horizontalSpace = new ()
+        {
+            X = 0,
+            Y = Pos.Bottom (orientationSelector),
+            Width = 11,
+            Title = "H_. Space",
+            Value = stylesSelector.HorizontalSpace,
+            BorderStyle = LineStyle.Dotted,
+        };
+        horizontalSpace.ValueChanging += HorizontalSpaceOnValueChanging;
+
+        CheckBox showBorderAndTitle = new ()
+        {
+            X = Pos.Right (horizontalSpace) + 1,
+            Y = Pos.Top (horizontalSpace),
+            Title = "Border _& Title",
+            CheckedState = CheckState.Checked,
+            BorderStyle = LineStyle.Dotted,
+        };
+        showBorderAndTitle.CheckedStateChanged += ShowBorderAndTitleOnCheckedStateChanged;
+
+        CheckBox canFocus = new ()
+        {
+            X = Pos.Right (showBorderAndTitle) + 1,
+            Y = Pos.Top (horizontalSpace),
+            Title = "_CanFocus",
+            CheckedState = CheckState.Checked,
+            BorderStyle = LineStyle.Dotted,
+        };
+        canFocus.CheckedStateChanged += CanFocusOnCheckedStateChanged;
+
+        optionSelectorsFrame = new ()
+        {
+            Y = Pos.Bottom (canFocus),
+            Width = Dim.Percent (50),
+            Height = Dim.Fill (),
+            Title = "O_ptionSelectors",
+            TabStop = TabBehavior.TabStop,
+            //InvertFocusAttribute = true
+        };
+        optionSelectorsFrame.ClearingViewport += (sender, args) =>
+                                                 {
+                                                     //               optionSelectorsFrame.SetAttributeForRole (optionSelectorsFrame.HasFocus ? VisualRole.Focus : VisualRole.Normal);
+                                                 };
+
+
+        Label label = new ()
+        {
+            Title = "Fo_ur Options:"
+        };
+
+        OptionSelector optionSelector = new ()
+        {
+            X = Pos.Right (label) + 1,
+            Title = "Fou_r Options",
+            BorderStyle = LineStyle.Dotted,
+            UsedHotKeys = { label.HotKey },
+            AssignHotKeys = true,
+            Labels = ["Option _1 (0)", "Option _2 (1)", "Option _3 (5) 你", "Option _Quattro (4) 你"],
+            Values = [0, 1, 5, 4],
+            Arrangement = ViewArrangement.Resizable,
+        };
+        optionSelectorsFrame.Add (label, optionSelector);
+
+        label = new ()
+        {
+            Y = Pos.Bottom (optionSelector),
+            Title = "<VisualRole_>:"
+        };
+
+        OptionSelector<VisualRole> optionSelectorT = new ()
+        {
+            X = Pos.Right (label) + 1,
+            Y = Pos.Bottom (optionSelector),
+            Title = "<Vi_sualRole>",
+            BorderStyle = LineStyle.Dotted,
+            UsedHotKeys = optionSelector.UsedHotKeys,
+            AssignHotKeys = true,
+        };
+
+        optionSelectorsFrame.Add (label, optionSelectorT);
+
+        flagSelectorsFrame = new ()
+        {
+            Y = Pos.Top (optionSelectorsFrame),
+            X = Pos.Right (optionSelectorsFrame),
+            Width = Dim.Fill (),
+            Height = Dim.Fill (),
+            Title = "_FlagSelectors",
+            TabStop = TabBehavior.TabStop
+        };
+
+        label = new ()
+        {
+            Title = "FlagSelector _(uint):"
+        };
+
+        FlagSelector flagSelector = new ()
+        {
+            X = Pos.Right (label) + 1,
+            UsedHotKeys = optionSelectorT.UsedHotKeys,
+            BorderStyle = LineStyle.Dotted,
+            Title = "FlagSe_lector (uint)",
+            AssignHotKeys = true,
+            Values =
+            [
+                0b_0001,
+                0b_0010,
+                0b_0100,
+                0b_1000,
+                0b_1111
+            ],
+            Labels =
+            [
+                "0x0001 One",
+                "0x0010 Two",
+                "0x0100 Quattro",
+                "0x1000 8",
+                "0x1111 Fifteen"
+            ]
+        };
+        flagSelectorsFrame.Add (label, flagSelector);
+
+        label = new ()
+        {
+            Y = Pos.Bottom (flagSelector),
+            Title = "_<ViewDiagnosticFlags>:"
+        };
+
+        FlagSelector<ViewDiagnosticFlags> flagSelectorT = new ()
+        {
+            X = Pos.Right (label) + 1,
+            BorderStyle = LineStyle.Dotted,
+            Title = "<ViewD_iagnosticFlags>",
+            Y = Pos.Bottom (flagSelector),
+            UsedHotKeys = flagSelector.UsedHotKeys,
+            AssignHotKeys = true,
+            Value = View.Diagnostics
+        };
+        flagSelectorsFrame.Add (label, flagSelectorT);
+        flagSelectorT.ValueChanged += (s, a) =>
+                                      {
+                                          View.Diagnostics = (ViewDiagnosticFlags)a.Value!;
+                                      };
+
+        appWindow.Add (orientationSelector, stylesSelector, horizontalSpace, showBorderAndTitle, canFocus, optionSelectorsFrame, flagSelectorsFrame);
+
+        // Run - Start the application.
+        Application.Run (appWindow);
+        appWindow.Dispose ();
+
+        // Shutdown - Calling Application.Shutdown is required.
+        Application.Shutdown ();
+
+        return;
+
+        void OrientationSelectorOnSelectedItemChanged (object? sender, EventArgs<Orientation?> e)
+        {
+            if (sender is not OptionSelector<Orientation> s)
+            {
+                return;
+            }
+
+            List<SelectorBase> selectors = GetAllSelectors ();
+            foreach (SelectorBase selector in selectors)
+            {
+                selector.Orientation = s.Value!.Value;
+            }
+        }
+
+        void StylesSelectorOnValueChanged (object? sender, EventArgs<SelectorStyles?> e)
+        {
+            if (sender is not FlagSelector<SelectorStyles> s)
+            {
+                return;
+            }
+
+            List<SelectorBase> selectors = GetAllSelectors ();
+
+            foreach (SelectorBase selector in selectors)
+            {
+                selector.Styles = s.Value!.Value;
+            }
+        }
+
+        void HorizontalSpaceOnValueChanging (object? sender, CancelEventArgs<int> e)
+        {
+            if (sender is not NumericUpDown<int> upDown || e.NewValue < 0)
+            {
+                e.Cancel = true;
+                return;
+            }
+
+            List<SelectorBase> selectors = GetAllSelectors ();
+
+            foreach (SelectorBase selector in selectors)
+            {
+                selector.HorizontalSpace = e.NewValue;
+            }
+        }
+
+
+        void ShowBorderAndTitleOnCheckedStateChanged (object? sender, EventArgs<CheckState> e)
+        {
+            if (sender is not CheckBox cb)
+            {
+                return;
+            }
+
+            List<SelectorBase> selectors = GetAllSelectors ();
+
+            foreach (SelectorBase selector in selectors)
+            {
+                selector.Border!.Thickness = cb.CheckedState == CheckState.Checked ? new (1) : new Thickness (0);
+            }
+        }
+
+        void CanFocusOnCheckedStateChanged (object? sender, EventArgs<CheckState> e)
+        {
+            if (sender is not CheckBox cb)
+            {
+                return;
+            }
+
+            List<SelectorBase> selectors = GetAllSelectors ();
+
+            foreach (SelectorBase selector in selectors)
+            {
+                selector.CanFocus = cb.CheckedState == CheckState.Checked;
+            }
+        }
+
+        List<SelectorBase> GetAllSelectors ()
+        {
+            List<SelectorBase> optionSelectors = [];
+            // ReSharper disable once AccessToModifiedClosure
+            optionSelectors.AddRange (optionSelectorsFrame!.SubViews.OfType<SelectorBase> ());
+            // ReSharper disable once AccessToModifiedClosure
+            optionSelectors.AddRange (flagSelectorsFrame!.SubViews.OfType<FlagSelector> ());
+
+            return optionSelectors;
+        }
+    }
+
+
+}

Examples/UICatalog/Scenarios/Shortcuts.cs

@@ -66,47 +66,26 @@ public class Shortcuts : Scenario
             {
                 Text = "_Align Keys",
                 CanFocus = false,
-                HighlightStates = MouseState.None
+                HighlightStates = MouseState.None,
+                CheckedState = CheckState.Checked
             },
             Key = Key.F5.WithCtrl.WithAlt.WithShift
         };
 
-        // ((CheckBox)vShortcut3.CommandView).CheckedStateChanging += (_, args) =>
         ((CheckBox)alignKeysShortcut.CommandView).CheckedStateChanging += (s, e) =>
                                                                           {
                                                                               if (alignKeysShortcut.CommandView is CheckBox cb)
                                                                               {
+                                                                                  bool align = e.Result == CheckState.Checked;
                                                                                   eventSource.Add (
                                                                                                    $"{alignKeysShortcut.Id}.CommandView.CheckedStateChanging: {cb.Text}");
                                                                                   eventLog.MoveDown ();
 
-                                                                                  var max = 0;
-
-                                                                                  IEnumerable<View> toAlign =
-                                                                                      Application.Top.SubViews.Where (
-                                                                                       v => v is Shortcut { Width: not DimAbsolute });
-                                                                                  IEnumerable<View> enumerable = toAlign as View [] ?? toAlign.ToArray ();
-
-                                                                                  if (e.Result == CheckState.Checked)
-                                                                                  {
-                                                                                      max = (from Shortcut? peer in enumerable
-                                                                                             select peer.Key.ToString ().GetColumns ()).Prepend (max)
-                                                                                          .Max ();
-
-                                                                                      foreach (View view in enumerable)
-                                                                                      {
-                                                                                          var peer = (Shortcut)view;
-                                                                                          max = Math.Max (max, peer.KeyView.Text.GetColumns ());
-                                                                                      }
-                                                                                  }
-
-                                                                                  foreach (View view in enumerable)
-                                                                                  {
-                                                                                      var peer = (Shortcut)view;
-                                                                                      peer.MinimumKeyTextSize = max;
-                                                                                  }
+                                                                                  AlignKeys (align);
                                                                               }
                                                                           };
+
+
         Application.Top.Add (alignKeysShortcut);
 
         var commandFirstShortcut = new Shortcut
@@ -136,9 +115,7 @@ public class Shortcuts : Scenario
                                                                                                       $"{commandFirstShortcut.Id}.CommandView.CheckedStateChanging: {cb.Text}");
                                                                                      eventLog.MoveDown ();
 
-                                                                                     IEnumerable<View> toAlign =
-                                                                                         Application.Top.SubViews.Where (
-                                                                                          v => v is Shortcut { Width: not DimAbsolute });
+                                                                                     IEnumerable<View> toAlign = Application.Top.SubViews.OfType<Shortcut> ();
                                                                                      IEnumerable<View> enumerable = toAlign as View [] ?? toAlign.ToArray ();
 
                                                                                      foreach (View view in enumerable)
@@ -166,8 +143,8 @@ public class Shortcuts : Scenario
             Y = Pos.Bottom (commandFirstShortcut),
             Width = Dim.Fill ()! - Dim.Width (eventLog),
             Key = Key.F4,
-            HelpText = "Changes all Command.CanFocus",
-            CommandView = new CheckBox { Text = "_CanFocus" }
+            HelpText = "Changes all CommandView.CanFocus",
+            CommandView = new CheckBox { Text = "_CommandView.CanFocus" },
         };
 
         ((CheckBox)canFocusShortcut.CommandView).CheckedStateChanging += (s, e) =>
@@ -179,13 +156,7 @@ public class Shortcuts : Scenario
 
                                                                                  //cb.CanFocus = e.NewValue == CheckState.Checked;
 
-                                                                                 foreach (Shortcut peer in Application.Top.SubViews.Where (v => v is Shortcut)!)
-                                                                                 {
-                                                                                     if (peer.CanFocus)
-                                                                                     {
-                                                                                         peer.CommandView.CanFocus = e.Result == CheckState.Checked;
-                                                                                     }
-                                                                                 }
+                                                                                 SetCanFocus (e.Result == CheckState.Checked);
                                                                              }
                                                                          };
         Application.Top.Add (canFocusShortcut);
@@ -224,37 +195,39 @@ public class Shortcuts : Scenario
 
         Application.Top.Add (buttonShortcut);
 
-        var radioGroupShortcut = new Shortcut
+        var optionSelectorShortcut = new Shortcut
         {
-            Id = "radioGroupShortcut",
+            Id = "optionSelectorShortcut",
+            HelpText = "Option Selector",
             X = 0,
             Y = Pos.Bottom (buttonShortcut),
             Key = Key.F2,
             Width = Dim.Fill ()! - Dim.Width (eventLog),
-            CommandView = new RadioGroup
+            CommandView = new OptionSelector ()
             {
                 Orientation = Orientation.Vertical,
-                RadioLabels = ["O_ne", "T_wo", "Th_ree", "Fo_ur"]
-            }
+                Labels = ["O_ne", "T_wo", "Th_ree", "Fo_ur"],
+                HighlightStates = MouseState.None,
+            },
         };
 
-        ((RadioGroup)radioGroupShortcut.CommandView).SelectedItemChanged += (o, args) =>
-                                                                            {
-                                                                                if (o is { })
+        ((OptionSelector)optionSelectorShortcut.CommandView).ValueChanged += (o, args) =>
                                                                                 {
-                                                                                    eventSource.Add (
-                                                                                                     $"SelectedItemChanged: {o.GetType ().Name} - {args.SelectedItem}");
-                                                                                    eventLog.MoveDown ();
-                                                                                }
-                                                                            };
+                                                                                    if (o is { })
+                                                                                    {
+                                                                                        eventSource.Add (
+                                                                                                         $"ValueChanged: {o.GetType ().Name} - {args.Value}");
+                                                                                        eventLog.MoveDown ();
+                                                                                    }
+                                                                                };
 
-        Application.Top.Add (radioGroupShortcut);
+        Application.Top.Add (optionSelectorShortcut);
 
         var sliderShortcut = new Shortcut
         {
             Id = "sliderShortcut",
             X = 0,
-            Y = Pos.Bottom (radioGroupShortcut),
+            Y = Pos.Bottom (optionSelectorShortcut),
             Width = Dim.Fill ()! - Dim.Width (eventLog),
             HelpText = "Sliders work!",
             CommandView = new Slider<string>
@@ -277,12 +250,34 @@ public class Shortcuts : Scenario
 
         Application.Top.Add (sliderShortcut);
 
+        ListView listView = new ListView ()
+        {
+            Height = Dim.Auto (),
+            Width = Dim.Auto (),
+            Title = "ListView",
+            BorderStyle = LineStyle.Single
+        };
+        listView.EnableForDesign ();
+
+        var listViewShortcut = new Shortcut ()
+        {
+            Id = "listViewShortcut",
+            X = 0,
+            Y = Pos.Bottom (sliderShortcut),
+            Width = Dim.Fill ()! - Dim.Width (eventLog),
+            HelpText = "A ListView with Border",
+            CommandView = listView,
+            Key = Key.F5.WithCtrl,
+        };
+
+        Application.Top.Add (listViewShortcut);
+
         var noCommandShortcut = new Shortcut
         {
             Id = "noCommandShortcut",
             X = 0,
-            Y = Pos.Bottom (sliderShortcut),
-            Width = Dim.Width (sliderShortcut),
+            Y = Pos.Bottom (listViewShortcut),
+            Width = Dim.Width (listViewShortcut),
             HelpText = "No Command",
             Key = Key.D0
         };
@@ -321,13 +316,15 @@ public class Shortcuts : Scenario
             Id = "framedShortcut",
             X = 0,
             Y = Pos.Bottom (noHelpShortcut) + 1,
-            Title = "Framed",
+            Width = Dim.Width (noHelpShortcut),
+            Title = "Framed Shortcut",
             Key = Key.K.WithCtrl,
-            Text = "Resize frame",
+            Text = "Help: You can resize this",
             BorderStyle = LineStyle.Dotted,
             Arrangement = ViewArrangement.RightResizable | ViewArrangement.BottomResizable
         };
-        framedShortcut.Orientation = Orientation.Horizontal;
+        framedShortcut.Border!.Settings = BorderSettings.Title;
+        //framedShortcut.Orientation = Orientation.Horizontal;
 
         if (framedShortcut.Padding is { })
         {
@@ -337,12 +334,12 @@ public class Shortcuts : Scenario
 
         if (framedShortcut.CommandView.Margin is { })
         {
-            framedShortcut.CommandView.Margin.SchemeName = framedShortcut.CommandView.SchemeName = "Error";
-            framedShortcut.HelpView.Margin!.SchemeName = framedShortcut.HelpView.SchemeName = "Dialog";
-            framedShortcut.KeyView.Margin!.SchemeName = framedShortcut.KeyView.SchemeName = "Menu";
+            framedShortcut.CommandView.SchemeName = framedShortcut.CommandView.SchemeName = SchemeManager.SchemesToSchemeName (Schemes.Dialog);
+            framedShortcut.HelpView.SchemeName = framedShortcut.HelpView.SchemeName = SchemeManager.SchemesToSchemeName (Schemes.Error);
+            framedShortcut.KeyView.SchemeName = framedShortcut.KeyView.SchemeName = SchemeManager.SchemesToSchemeName (Schemes.Base);
         }
 
-        framedShortcut.SchemeName = "TopLevel";
+        framedShortcut.SchemeName = SchemeManager.SchemesToSchemeName (Schemes.Toplevel);
         Application.Top.Add (framedShortcut);
 
         // Horizontal
@@ -504,7 +501,7 @@ public class Shortcuts : Scenario
                                                   eventSource.Add (
                                                                    $"{shortcut!.Id}.CommandView.Selecting: {shortcut!.CommandView.Text} {shortcut!.CommandView.GetType ().Name}");
                                                   eventLog.MoveDown ();
-                                                  args.Handled = true;
+                                                  //args.Handled = true;
                                               };
 
             shortcut.Accepting += (o, args) =>
@@ -513,7 +510,7 @@ public class Shortcuts : Scenario
                                       eventLog.MoveDown ();
 
                                       // We don't want this to exit the Scenario
-                                      args.Handled = true;
+                                      //args.Handled = true;
                                   };
 
             shortcut.CommandView.Accepting += (o, args) =>
@@ -523,6 +520,46 @@ public class Shortcuts : Scenario
                                                   eventLog.MoveDown ();
                                               };
         }
+
+        SetCanFocus (false);
+
+        AlignKeys (true);
+
+        return;
+
+        void SetCanFocus (bool canFocus)
+        {
+            foreach (Shortcut peer in Application.Top!.SubViews.OfType<Shortcut> ())
+            {
+                if (peer.CanFocus)
+                {
+                    peer.CommandView.CanFocus = canFocus;
+                }
+            }
+        }
+
+        void AlignKeys (bool align)
+        {
+            var max = 0;
+
+            IEnumerable<Shortcut> toAlign = Application.Top!.SubViews.OfType<Shortcut> ().Where(s => !s.Y.Has<PosAnchorEnd>(out _)).Cast<Shortcut>();
+            IEnumerable<Shortcut> enumerable = toAlign as Shortcut [] ?? toAlign.ToArray ();
+
+            if (align)
+            {
+                max = (from Shortcut? peer in enumerable
+                       select peer!.Key.ToString ().GetColumns ()).Prepend (max)
+                                                                  .Max ();
+
+                max = enumerable.Select (peer => peer.KeyView.Text.GetColumns ()).Prepend (max).Max ();
+            }
+
+            foreach (Shortcut shortcut in enumerable)
+            {
+                Shortcut peer = shortcut;
+                peer.MinimumKeyTextSize = max;
+            }
+        }
     }
 
     private void Button_Clicked (object? sender, CommandEventArgs e)

Examples/UICatalog/Scenarios/TextAlignmentAndDirection.cs

@@ -492,18 +492,18 @@ public class TextAlignmentAndDirection : Scenario
 
         // JUSTIFY OPTIONS
 
-        var justifyOptions = new RadioGroup
+        var justifyOptions = new OptionSelector
         {
             X = Pos.Left (justifyCheckbox) + 1,
             Y = Pos.Y (justifyCheckbox) + 1,
             Width = Dim.Fill (9),
-            RadioLabels = ["Current direction", "Opposite direction", "FIll Both"],
+            Labels = ["Current direction", "Opposite direction", "FIll Both"],
             Enabled = false
         };
 
         justifyCheckbox.CheckedStateChanging += (s, e) => ToggleJustify (e.Result != CheckState.Checked);
 
-        justifyOptions.SelectedItemChanged += (s, e) => { ToggleJustify (false, true); };
+        justifyOptions.ValueChanged += (_, _) => { ToggleJustify (false, true); };
 
         app.Add (justifyOptions);
 
@@ -541,17 +541,17 @@ public class TextAlignmentAndDirection : Scenario
 
         List<TextDirection> directionsEnum = Enum.GetValues (typeof (TextDirection)).Cast<TextDirection> ().ToList ();
 
-        var directionOptions = new RadioGroup
+        var directionOptions = new OptionSelector
         {
             X = Pos.Right (container) + 1,
             Y = Pos.Bottom (wrapCheckbox) + 1,
             Width = Dim.Fill (10),
             Height = Dim.Fill (1),
             HotKeySpecifier = (Rune)'\xffff',
-            RadioLabels = directionsEnum.Select (e => e.ToString ()).ToArray ()
+            Labels = directionsEnum.Select (e => e.ToString ()).ToArray ()
         };
 
-        directionOptions.SelectedItemChanged += (s, ev) =>
+        directionOptions.ValueChanged += (s, ev) =>
                                                 {
                                                     bool justChecked = justifyCheckbox.CheckedState == CheckState.Checked;
 
@@ -560,9 +560,9 @@ public class TextAlignmentAndDirection : Scenario
                                                         ToggleJustify (true);
                                                     }
 
-                                                    foreach (View v in multiLineLabels)
+                                                    foreach (View v in multiLineLabels.Where (v => ev.Value is { }))
                                                     {
-                                                        v.TextDirection = (TextDirection)ev.SelectedItem;
+                                                        v.TextDirection = (TextDirection)ev.Value!.Value;
                                                     }
 
                                                     if (justChecked)
@@ -612,7 +612,7 @@ public class TextAlignmentAndDirection : Scenario
 
                     if (TextFormatter.IsVerticalDirection (t.TextDirection))
                     {
-                        switch (justifyOptions.SelectedItem)
+                        switch (justifyOptions.Value)
                         {
                             case 0:
                                 t.VerticalTextAlignment = Alignment.Fill;
@@ -630,7 +630,7 @@ public class TextAlignmentAndDirection : Scenario
                     }
                     else
                     {
-                        switch (justifyOptions.SelectedItem)
+                        switch (justifyOptions.Value)
                         {
                             case 0:
                                 t.TextAlignment = Alignment.Fill;

Examples/UICatalog/Scenarios/TextInputControls.cs

@@ -68,7 +68,7 @@ public class TextInputControls : Scenario
             X = Pos.Right (label) + 1,
             Y = Pos.Bottom (textField),
             Width = Dim.Percent (50) - 1,
-            Caption = "TextField with caption"
+            Title = "TextField with caption"
         };
 
         win.Add (textField);
@@ -498,5 +498,5 @@ public class TextInputControls : Scenario
 
 
 
-    private void TimeChanged (object sender, DateTimeEventArgs<TimeSpan> e) { _labelMirroringTimeField.Text = _timeField.Text; }
+    private void TimeChanged (object sender, EventArgs<TimeSpan> e) { _labelMirroringTimeField.Text = _timeField.Text; }
 }

Examples/UICatalog/Scenarios/Themes.cs

@@ -23,26 +23,26 @@ public sealed class Themes : Scenario
         };
 
         string[]  options = ThemeManager.GetThemeNames ().Select (option => option = "_" + option).ToArray ();
-        RadioGroup themeOptionSelector = new ()
+        OptionSelector themeOptionSelector = new ()
         {
             Title = "_Themes",
             BorderStyle = LineStyle.Rounded,
             Width = Dim.Auto (),
             Height = Dim.Auto (),
-            RadioLabels= options,
-            SelectedItem = ThemeManager.GetThemeNames ().IndexOf (ThemeManager.Theme)
+            Labels= options,
+            Value = ThemeManager.GetThemeNames ().IndexOf (ThemeManager.Theme)
         };
         themeOptionSelector.Border!.Thickness = new (0, 1, 0, 0);
         themeOptionSelector.Margin!.Thickness = new (0, 0, 1, 0);
 
-        themeOptionSelector.SelectedItemChanged += (sender, args) =>
+        themeOptionSelector.ValueChanged += (sender, args) =>
                                              {
-                                                 RadioGroup? optionSelector = sender as RadioGroup;
+                                                 OptionSelector? optionSelector = sender as OptionSelector;
                                                  if (optionSelector is null)
                                                  {
                                                      return;
                                                  }
-                                                 var newTheme = optionSelector!.RadioLabels! [(int)args.SelectedItem!] as string;
+                                                 var newTheme = optionSelector!.Labels! [(int)args.Value!] as string;
                                                  // strip off the leading underscore
                                                  ThemeManager.Theme = newTheme!.Substring (1);
                                                  ConfigurationManager.Apply ();

Examples/UICatalog/Scenarios/TimeAndDate.cs

@@ -1,4 +1,5 @@
-using System;
+#nullable enable
+using System;
 
 namespace UICatalog.Scenarios;
 
@@ -7,12 +8,12 @@ namespace UICatalog.Scenarios;
 [ScenarioCategory ("DateTime")]
 public class TimeAndDate : Scenario
 {
-    private Label _lblDateFmt;
-    private Label _lblNewDate;
-    private Label _lblNewTime;
-    private Label _lblOldDate;
-    private Label _lblOldTime;
-    private Label _lblTimeFmt;
+    private Label? _lblDateFmt;
+    private Label? _lblNewDate;
+    private Label? _lblNewTime;
+    private Label? _lblOldDate;
+    private Label? _lblOldTime;
+    private Label? _lblTimeFmt;
 
     public override void Main ()
     {
@@ -143,17 +144,13 @@ public class TimeAndDate : Scenario
         Application.Shutdown ();
     }
 
-    private void DateChanged (object sender, DateTimeEventArgs<DateTime> e)
+    private void DateChanged (object? sender, EventArgs<DateTime> e)
     {
-        _lblOldDate.Text = $"Old Date: {e.OldValue}";
-        _lblNewDate.Text = $"New Date: {e.NewValue}";
-        _lblDateFmt.Text = $"Date Format: {e.Format}";
+        _lblNewDate!.Text = $"New Date: {e.Value}";
     }
 
-    private void TimeChanged (object sender, DateTimeEventArgs<TimeSpan> e)
+    private void TimeChanged (object? sender, EventArgs<TimeSpan> e)
     {
-        _lblOldTime.Text = $"Old Time: {e.OldValue}";
-        _lblNewTime.Text = $"New Time: {e.NewValue}";
-        _lblTimeFmt.Text = $"Time Format: {e.Format}";
+        _lblNewTime!.Text = $"New Time: {e.Value}";
     }
 }

Examples/UICatalog/Scenarios/TreeViewFileSystem.cs

@@ -414,7 +414,7 @@ public class TreeViewFileSystem : Scenario
 
     private void ShowContextMenu (Point screenPoint, IFileSystemInfo forObject)
     {
-        PopoverMenu? contextMenu = new ([new ("Properties", $"Show {forObject.Name} properties", () => ShowPropertiesOf (forObject))]);
+        PopoverMenu contextMenu = new ([new ("Properties", $"Show {forObject.Name} properties", () => ShowPropertiesOf (forObject))]);
 
         // Registering with the PopoverManager will ensure that the context menu is closed when the view is no longer focused
         // and the context menu is disposed when it is closed.

Examples/UICatalog/Scenarios/Unicode.cs

@@ -71,8 +71,7 @@ public class UnicodeInMenu : Scenario
         appWindow.Add (menu);
 
         var statusBar = new StatusBar (
-                                       new Shortcut []
-                                       {
+                                       [
                                            new (
                                                 Application.QuitKey,
                                                 "Выход",
@@ -80,7 +79,7 @@ public class UnicodeInMenu : Scenario
                                                ),
                                            new (Key.F2, "Создать", null),
                                            new (Key.F3, "Со_хранить", null)
-                                       }
+                                       ]
                                       );
         appWindow.Add (statusBar);
 
@@ -145,13 +144,13 @@ public class UnicodeInMenu : Scenario
         };
         appWindow.Add (checkBox, checkBoxRight);
 
-        label = new () { X = Pos.X (label), Y = Pos.Bottom (checkBoxRight) + 1, Text = "ComboBox:" };
-        appWindow.Add (label);
-        var comboBox = new ComboBox { X = 20, Y = Pos.Y (label), Width = Dim.Percent (50) };
-        comboBox.SetSource (new ObservableCollection<string> { gitString, "Со_хранить" });
+        //label = new () { X = Pos.X (label), Y = Pos.Bottom (checkBoxRight) + 1, Text = "ComboBox:" };
+        //appWindow.Add (label);
+        //var comboBox = new ComboBox { X = 20, Y = Pos.Y (label), Width = Dim.Percent (50) };
+        //comboBox.SetSource (new ObservableCollection<string> { gitString, "Со_хранить" });
 
-        appWindow.Add (comboBox);
-        comboBox.Text = gitString;
+        //appWindow.Add (comboBox);
+        //comboBox.Text = gitString;
 
         label = new () { X = Pos.X (label), Y = Pos.Bottom (label) + 2, Text = "HexView:" };
         appWindow.Add (label);
@@ -177,19 +176,19 @@ public class UnicodeInMenu : Scenario
         };
         appWindow.Add (listView);
 
-        label = new () { X = Pos.X (label), Y = Pos.Bottom (listView) + 1, Text = "RadioGroup:" };
+        label = new () { X = Pos.X (label), Y = Pos.Bottom (listView) + 1, Text = "OptionSelector:" };
         appWindow.Add (label);
 
-        var radioGroup = new RadioGroup
+        var optionSelector = new OptionSelector
         {
             X = 20,
             Y = Pos.Y (label),
             Width = Dim.Percent (60),
-            RadioLabels = new [] { "item #1", gitString, "Со_хранить", "𝔽𝕆𝕆𝔹𝔸ℝ" }
+            Labels = new [] { "item #1", gitString, "Со_хранить", "𝔽𝕆𝕆𝔹𝔸ℝ" }
         };
-        appWindow.Add (radioGroup);
+        appWindow.Add (optionSelector);
 
-        label = new () { X = Pos.X (label), Y = Pos.Bottom (radioGroup) + 1, Text = "TextField:" };
+        label = new () { X = Pos.X (label), Y = Pos.Bottom (optionSelector) + 1, Text = "TextField:" };
         appWindow.Add (label);
 
         var textField = new TextField

Examples/UICatalog/Scenarios/ViewportSettings.cs

@@ -178,10 +178,10 @@ public class ViewportSettings : Scenario
         buttonAnchored.Accepting += (sender, args) => MessageBox.Query ("Hi", $"You pressed {((Button)sender)?.Text}", "_Ok");
 
         view.Margin!.Data = "Margin";
-        view.Margin.Thickness = new (0);
+        view.Margin!.Thickness = new (0);
 
         view.Border!.Data = "Border";
-        view.Border.Thickness = new (3);
+        view.Border!.Thickness = new (3);
 
         view.Padding.Data = "Padding";
 

Examples/UICatalog/Scenarios/WindowsAndFrameViews.cs

@@ -43,7 +43,7 @@ public class WindowsAndFrameViews : Scenario
             Arrangement = ViewArrangement.Overlapped | ViewArrangement.Movable | ViewArrangement.Resizable
         };
         win.Padding.Thickness = new (padding);
-        win.Margin.Thickness = new (margin);
+        win.Margin!.Thickness = new (margin);
 
         var paddingButton = new Button
         {

Examples/UICatalog/Scenarios/Wizards.cs

@@ -162,11 +162,11 @@ public class Wizards : Scenario
                                            firstStep.HelpText =
                                                "This is the End User License Agreement.\n\n\n\n\n\nThis is a test of the emergency broadcast system. This is a test of the emergency broadcast system.\nThis is a test of the emergency broadcast system.\n\n\nThis is a test of the emergency broadcast system.\n\nThis is a test of the emergency broadcast system.\n\n\n\nThe end of the EULA.";
 
-                                           RadioGroup radioGroup = new ()
+                                           OptionSelector optionSelector = new ()
                                            {
-                                               RadioLabels = ["_One", "_Two", "_3"]
+                                               Labels = ["_One", "_Two", "_3"]
                                            };
-                                           firstStep.Add (radioGroup);
+                                           firstStep.Add (optionSelector);
 
                                            wizard.AddStep (firstStep);
 
@@ -184,12 +184,12 @@ public class Wizards : Scenario
                                                Text = "Press Me to Rename Step", X = Pos.Right (buttonLbl), Y = Pos.Top (buttonLbl)
                                            };
 
-                                           RadioGroup radioGroup2 = new ()
+                                           OptionSelector optionSelecor2 = new ()
                                            {
-                                               RadioLabels = ["_A", "_B", "_C"],
+                                               Labels = ["_A", "_B", "_C"],
                                                Orientation = Orientation.Horizontal
                                            };
-                                           secondStep.Add (radioGroup2);
+                                           secondStep.Add (optionSelecor2);
 
                                            button.Accepting += (s, e) =>
                                                             {

Examples/UICatalog/UICatalog.cs

@@ -80,7 +80,7 @@ public class UICatalog
         // Get allowed driver names
         string? [] allowedDrivers = Application.GetDriverTypes ().Item2.ToArray ();
 
-        Option<string> driverOption = new Option<string> ("--driver", "The IConsoleDriver to use.")
+        Option<string> driverOption = new Option<string> ("--driver", "The IDriver to use.")
             .FromAmong (allowedDrivers!);
         driverOption.SetDefaultValue (string.Empty);
         driverOption.AddAlias ("-d");
@@ -451,7 +451,7 @@ public class UICatalog
             scenario.StartBenchmark ();
         }
 
-        Application.Init (driverName: _forceDriver);
+        Application.ForceDriver = _forceDriver!;
 
         scenario.Main ();
 
@@ -517,7 +517,7 @@ public class UICatalog
 
         if (benchmarkWindow.Border is { })
         {
-            benchmarkWindow.Border.Thickness = new (0, 0, 0, 0);
+            benchmarkWindow.Border!.Thickness = new (0, 0, 0, 0);
         }
 
         TableView resultsTableView = new ()
@@ -635,7 +635,7 @@ public class UICatalog
         if (!View.EnableDebugIDisposableAsserts)
         {
             View.Instances.Clear ();
-            RunState.Instances.Clear ();
+            SessionToken.Instances.Clear ();
 
             return;
         }
@@ -650,15 +650,15 @@ public class UICatalog
 
         View.Instances.Clear ();
 
-        // Validate there are no outstanding Application.RunState-based instances 
+        // Validate there are no outstanding Application sessions
         // after a scenario was selected to run. This proves the main UI Catalog
         // 'app' closed cleanly.
-        foreach (RunState? inst in RunState.Instances)
+        foreach (SessionToken? inst in SessionToken.Instances)
         {
             Debug.Assert (inst.WasDisposed);
         }
 
-        RunState.Instances.Clear ();
+        SessionToken.Instances.Clear ();
 #endif
     }
 }

Examples/UICatalog/UICatalogTop.cs

@@ -96,9 +96,9 @@ public class UICatalogTop : Toplevel
 
     private readonly MenuBarv2? _menuBar;
     private CheckBox? _force16ColorsMenuItemCb;
-    private OptionSelector? _themesRg;
-    private OptionSelector? _topSchemeRg;
-    private OptionSelector? _logLevelRg;
+    private OptionSelector? _themesSelector;
+    private OptionSelector? _topSchemesSelector;
+    private OptionSelector? _logLevelSelector;
     private FlagSelector<ViewDiagnosticFlags>? _diagnosticFlagsSelector;
     private CheckBox? _disableMouseCb;
 
@@ -126,13 +126,13 @@ public class UICatalogTop : Toplevel
                                           [
                                               new MenuItemv2 (
                                                               "_Documentation",
-                                                              "",
+                                                              "API docs",
                                                               () => OpenUrl ("https://gui-cs.github.io/Terminal.Gui"),
                                                               Key.F1
                                                              ),
                                               new MenuItemv2 (
                                                               "_README",
-                                                              "",
+                                                              "Project readme",
                                                               () => OpenUrl ("https://github.com/gui-cs/Terminal.Gui"),
                                                               Key.F2
                                                              ),
@@ -163,7 +163,10 @@ public class UICatalogTop : Toplevel
             _force16ColorsMenuItemCb = new ()
             {
                 Title = "Force _16 Colors",
-                CheckedState = Application.Force16Colors ? CheckState.Checked : CheckState.UnChecked
+                CheckedState = Application.Force16Colors ? CheckState.Checked : CheckState.UnChecked,
+                // Best practice for CheckBoxes in menus is to disable focus and highlight states
+                CanFocus = false,
+                HighlightStates = MouseState.None
             };
 
             _force16ColorsMenuItemCb.CheckedStateChanging += (sender, args) =>
@@ -194,23 +197,25 @@ public class UICatalogTop : Toplevel
 
             if (ConfigurationManager.IsEnabled)
             {
-                _themesRg = new ()
+                _themesSelector = new ()
                 {
-                    HighlightStates = Terminal.Gui.ViewBase.MouseState.None,
+                    // HighlightStates = MouseState.In,
+                    CanFocus = true,
+                    // InvertFocusAttribute = true
                 };
 
-                _themesRg.SelectedItemChanged += (_, args) =>
+                _themesSelector.ValueChanged += (_, args) =>
                                                  {
-                                                     if (args.SelectedItem is null)
+                                                     if (args.Value is null)
                                                      {
                                                          return;
                                                      }
-                                                     ThemeManager.Theme = ThemeManager.GetThemeNames () [args.SelectedItem!.Value];
+                                                     ThemeManager.Theme = ThemeManager.GetThemeNames () [(int)args.Value];
                                                  };
 
                 var menuItem = new MenuItemv2
                 {
-                    CommandView = _themesRg,
+                    CommandView = _themesSelector,
                     HelpText = "Cycle Through Themes",
                     Key = Key.T.WithCtrl
                 };
@@ -218,18 +223,18 @@ public class UICatalogTop : Toplevel
 
                 menuItems.Add (new Line ());
 
-                _topSchemeRg = new ()
+                _topSchemesSelector = new ()
                 {
-                    HighlightStates = Terminal.Gui.ViewBase.MouseState.None,
+                    //  HighlightStates = MouseState.In,
                 };
 
-                _topSchemeRg.SelectedItemChanged += (_, args) =>
+                _topSchemesSelector.ValueChanged += (_, args) =>
                                                     {
-                                                        if (args.SelectedItem is null)
+                                                        if (args.Value is null)
                                                         {
                                                             return;
                                                         }
-                                                        CachedTopLevelScheme = SchemeManager.GetSchemesForCurrentTheme ()!.Keys.ToArray () [args.SelectedItem!.Value];
+                                                        CachedTopLevelScheme = SchemeManager.GetSchemesForCurrentTheme ()!.Keys.ToArray () [(int)args.Value];
                                                         SchemeName = CachedTopLevelScheme;
                                                         SetNeedsDraw ();
                                                     };
@@ -241,7 +246,7 @@ public class UICatalogTop : Toplevel
                                    [
                                        new ()
                                        {
-                                           CommandView = _topSchemeRg,
+                                           CommandView = _topSchemesSelector,
                                            HelpText = "Cycle Through schemes",
                                            Key = Key.S.WithCtrl
                                        }
@@ -269,12 +274,12 @@ public class UICatalogTop : Toplevel
 
             _diagnosticFlagsSelector = new ()
             {
-                CanFocus = true,
-                Styles = FlagSelectorStyles.ShowNone,
-                HighlightStates = Terminal.Gui.ViewBase.MouseState.None,
+                Styles = SelectorStyles.ShowNoneFlag,
+                CanFocus = true
+
             };
             _diagnosticFlagsSelector.UsedHotKeys.Add (Key.D);
-            _diagnosticFlagsSelector.AssignHotKeysToCheckBoxes = true;
+            _diagnosticFlagsSelector.AssignHotKeys = true;
             _diagnosticFlagsSelector.Value = Diagnostics;
             _diagnosticFlagsSelector.ValueChanged += (sender, args) =>
                                                      {
@@ -294,7 +299,10 @@ public class UICatalogTop : Toplevel
             _disableMouseCb = new ()
             {
                 Title = "_Disable Mouse",
-                CheckedState = Application.IsMouseDisabled ? CheckState.Checked : CheckState.UnChecked
+                CheckedState = Application.IsMouseDisabled ? CheckState.Checked : CheckState.UnChecked,
+                // Best practice for CheckBoxes in menus is to disable focus and highlight states
+                CanFocus = false,
+                HighlightStates = MouseState.None
             };
 
             _disableMouseCb.CheckedStateChanged += (_, args) => { Application.IsMouseDisabled = args.Value == CheckState.Checked; };
@@ -315,17 +323,17 @@ public class UICatalogTop : Toplevel
 
             LogLevel [] logLevels = Enum.GetValues<LogLevel> ();
 
-            _logLevelRg = new ()
+            _logLevelSelector = new ()
             {
-                AssignHotKeysToCheckBoxes = true,
-                Options = Enum.GetNames<LogLevel> (),
-                SelectedItem = logLevels.ToList ().IndexOf (Enum.Parse<LogLevel> (UICatalog.Options.DebugLogLevel)),
-                HighlightStates = Terminal.Gui.ViewBase.MouseState.In
+                AssignHotKeys = true,
+                Labels = Enum.GetNames<LogLevel> (),
+                Value = logLevels.ToList ().IndexOf (Enum.Parse<LogLevel> (UICatalog.Options.DebugLogLevel)),
+                // HighlightStates = MouseState.In,
             };
 
-            _logLevelRg.SelectedItemChanged += (_, args) =>
+            _logLevelSelector.ValueChanged += (_, args) =>
             {
-                UICatalog.Options = UICatalog.Options with { DebugLogLevel = Enum.GetName (logLevels [args.SelectedItem!.Value])! };
+                UICatalog.Options = UICatalog.Options with { DebugLogLevel = Enum.GetName (logLevels [args.Value!.Value])! };
 
                 UICatalog.LogLevelSwitch.MinimumLevel =
                     UICatalog.LogLevelToLogEventLevel (Enum.Parse<LogLevel> (UICatalog.Options.DebugLogLevel));
@@ -334,7 +342,7 @@ public class UICatalogTop : Toplevel
             menuItems.Add (
                            new MenuItemv2
                            {
-                               CommandView = _logLevelRg,
+                               CommandView = _logLevelSelector,
                                HelpText = "Cycle Through Log Levels",
                                Key = Key.L.WithCtrl
                            });
@@ -356,27 +364,27 @@ public class UICatalogTop : Toplevel
 
     private void UpdateThemesMenu ()
     {
-        if (_themesRg is null)
+        if (_themesSelector is null)
         {
             return;
         }
 
-        _themesRg.SelectedItem = null;
-        _themesRg.AssignHotKeysToCheckBoxes = true;
-        _themesRg.UsedHotKeys.Clear ();
-        _themesRg.Options = ThemeManager.GetThemeNames ();
-        _themesRg.SelectedItem =ThemeManager.GetThemeNames ().IndexOf (ThemeManager.GetCurrentThemeName ());
+        _themesSelector.Value = null;
+        _themesSelector.AssignHotKeys = true;
+        _themesSelector.UsedHotKeys.Clear ();
+        _themesSelector.Labels = ThemeManager.GetThemeNames ().ToArray ();
+        _themesSelector.Value = ThemeManager.GetThemeNames ().IndexOf (ThemeManager.GetCurrentThemeName ());
 
-        if (_topSchemeRg is null)
+        if (_topSchemesSelector is null)
         {
             return;
         }
 
-        _topSchemeRg.AssignHotKeysToCheckBoxes = true;
-        _topSchemeRg.UsedHotKeys.Clear ();
-        int? selectedScheme = _topSchemeRg.SelectedItem;
-        _topSchemeRg.Options = SchemeManager.GetSchemeNames ();
-        _topSchemeRg.SelectedItem = selectedScheme;
+        _topSchemesSelector.AssignHotKeys = true;
+        _topSchemesSelector.UsedHotKeys.Clear ();
+        int? selectedScheme = _topSchemesSelector.Value;
+        _topSchemesSelector.Labels = SchemeManager.GetSchemeNames ().ToArray ();
+        _topSchemesSelector.Value = selectedScheme;
 
         if (CachedTopLevelScheme is null || !SchemeManager.GetSchemeNames ().Contains (CachedTopLevelScheme))
         {
@@ -387,7 +395,7 @@ public class UICatalogTop : Toplevel
         // if the item is in bounds then select it
         if (newSelectedItem >= 0 && newSelectedItem < SchemeManager.GetSchemeNames ().Count)
         {
-            _topSchemeRg.SelectedItem = newSelectedItem;
+            _topSchemesSelector.Value = newSelectedItem;
         }
     }
 

README.md

@@ -1,6 +1,5 @@
-![.NET Core](https://github.com/gui-cs/Terminal.Gui/workflows/.NET%20Core/badge.svg?branch=develop)
 [![Version](https://img.shields.io/nuget/v/Terminal.Gui.svg)](https://www.nuget.org/packages/Terminal.Gui)
-![Code Coverage](https://img.shields.io/endpoint?url=https://gist.githubusercontent.com/migueldeicaza/90ef67a684cb71db1817921a970f8d27/raw/code-coverage.json)
+[![codecov](https://codecov.io/gh/gui-cs/Terminal.Gui/graph/badge.svg?token=1Ac9gyGtrj)](https://codecov.io/gh/gui-cs/Terminal.Gui)
 [![Downloads](https://img.shields.io/nuget/dt/Terminal.Gui)](https://www.nuget.org/packages/Terminal.Gui)
 [![License](https://img.shields.io/github/license/gui-cs/gui.cs.svg)](LICENSE)
 ![Bugs](https://img.shields.io/github/issues/gui-cs/gui.cs/bug)

Scripts/Run-LocalCoverage.ps1

@@ -0,0 +1,109 @@
+# ------------------------------------------------------------
+# Run-LocalCoverage.ps1
+# Local-only: Unit + Parallel + Integration tests
+# Quiet, merged coverage in /Tests
+# ------------------------------------------------------------
+
+# 1. Define paths
+$testDir    = Join-Path $PWD "Tests"
+$covDir     = Join-Path $testDir "coverage"
+$reportDir  = Join-Path $testDir "report"
+$resultsDir = Join-Path $testDir "TestResults"
+$mergedFile = Join-Path $covDir "coverage.merged.cobertura.xml"
+
+# 2. Clean old results - INCLUDING TestResults directory
+Write-Host "Cleaning old coverage files and test results..."
+Remove-Item -Recurse -Force $covDir, $reportDir, $resultsDir -ErrorAction SilentlyContinue
+New-Item -ItemType Directory -Path $covDir, $reportDir -Force | Out-Null
+
+dotnet build --configuration Debug --no-restore
+
+# ------------------------------------------------------------
+# 3. Run UNIT TESTS (non-parallel)
+# ------------------------------------------------------------
+Write-Host "`nRunning UnitTests (quiet)..."
+dotnet test Tests/UnitTests `
+  --no-build `
+  --verbosity minimal `
+  --collect:"XPlat Code Coverage" `
+  --settings Tests/UnitTests/runsettings.coverage.xml `
+  --blame-hang-timeout 10s
+
+# ------------------------------------------------------------
+# 4. Run UNIT TESTS (parallel)
+# ------------------------------------------------------------
+Write-Host "`nRunning UnitTestsParallelizable (quiet)..."
+dotnet test Tests/UnitTestsParallelizable `
+  --no-build `
+  --verbosity minimal `
+  --collect:"XPlat Code Coverage" `
+  --settings Tests/UnitTestsParallelizable/runsettings.coverage.xml
+
+# ------------------------------------------------------------
+# 5. Run INTEGRATION TESTS
+# ------------------------------------------------------------
+Write-Host "`nRunning IntegrationTests (quiet)..."
+dotnet test Tests/IntegrationTests `
+  --no-build `
+  --verbosity minimal `
+  --collect:"XPlat Code Coverage" `
+  --settings Tests/IntegrationTests/runsettings.coverage.xml
+
+# ------------------------------------------------------------
+# 6. Find ALL coverage files (from all 3 projects) - NOW SCOPED TO Tests/TestResults
+# ------------------------------------------------------------
+Write-Host "`nCollecting coverage files..."
+$covFiles = Get-ChildItem -Path $resultsDir -Recurse -Filter coverage.cobertura.xml -File -ErrorAction SilentlyContinue
+
+if (-not $covFiles) {
+    Write-Error "No coverage files found in $resultsDir. Did all tests run successfully?"
+    exit 1
+}
+
+# ------------------------------------------------------------
+# 7. Move to Tests/coverage
+# ------------------------------------------------------------
+Write-Host "Moving $($covFiles.Count) coverage file(s) to $covDir..."
+$fileIndex = 1
+foreach ($f in $covFiles) {
+    $destFile = Join-Path $covDir "coverage.$fileIndex.cobertura.xml"
+    Copy-Item $f.FullName -Destination $destFile -Force
+    $fileIndex++
+}
+
+# ------------------------------------------------------------
+# 8. Merge into one file
+# ------------------------------------------------------------
+Write-Host "Merging coverage from all test projects..."
+dotnet-coverage merge `
+    -o $mergedFile `
+    -f cobertura `
+    "$covDir\*.cobertura.xml"
+
+# ------------------------------------------------------------
+# 9. Generate HTML + text report
+# ------------------------------------------------------------
+Write-Host "Generating final HTML report..."
+reportgenerator `
+    -reports:$mergedFile `
+    -targetdir:$reportDir `
+    -reporttypes:"Html;TextSummary"
+
+# ------------------------------------------------------------
+# 10. Show summary + open report
+# ------------------------------------------------------------
+Write-Host "`n=== Final Coverage Summary (Unit + Integration) ==="
+Get-Content "$reportDir\Summary.txt"
+
+$indexHtml = Join-Path $reportDir "index.html"
+if (Test-Path $indexHtml) {
+    Write-Host "Opening report in browser..."
+    Start-Process $indexHtml
+} else {
+    Write-Warning "HTML report not found at $indexHtml"
+}
+
+Write-Host "`nCoverage artifacts:"
+Write-Host "  - Merged coverage: $mergedFile"
+Write-Host "  - HTML report:     $reportDir\index.html"
+Write-Host "  - Test results:    $resultsDir"

Terminal.Gui.Analyzers.Tests/HandledEventArgsAnalyzerTests.cs

@@ -1,7 +1,8 @@
-using Terminal.Gui.Input;
+using Terminal.Gui.Analyzers;
+using Terminal.Gui.Input;
 using Terminal.Gui.Views;
 
-namespace Terminal.Gui.Analyzers.Tests;
+namespace Analyzers.Tests;
 
 public class HandledEventArgsAnalyzerTests
 {

Terminal.Gui.Analyzers.Tests/ProjectBuilder.cs

@@ -17,10 +17,10 @@ using JetBrains.Annotations;
 
 public sealed class ProjectBuilder
 {
-    private string _sourceCode;
-    private string _expectedFixedCode;
-    private DiagnosticAnalyzer _analyzer;
-    private CodeFixProvider _codeFix;
+    private string? _sourceCode;
+    private string? _expectedFixedCode;
+    private DiagnosticAnalyzer? _analyzer;
+    private CodeFixProvider? _codeFix;
 
     public ProjectBuilder WithSourceCode (string source)
     {
@@ -59,20 +59,22 @@ public sealed class ProjectBuilder
         }
 
         // Parse original document
-        var document = CreateDocument (_sourceCode);
-        var compilation = await document.Project.GetCompilationAsync ();
+        Document document = CreateDocument (_sourceCode);
+        Compilation? compilation = await document.Project.GetCompilationAsync ();
 
-        var diagnostics = compilation.GetDiagnostics ();
-        var errors = diagnostics.Where (d => d.Severity == DiagnosticSeverity.Error);
+        ImmutableArray<Diagnostic> diagnostics = compilation!.GetDiagnostics ();
+        IEnumerable<Diagnostic> errors = diagnostics.Where (d => d.Severity == DiagnosticSeverity.Error);
 
-        if (errors.Any ())
+        IEnumerable<Diagnostic> enumerable = errors as Diagnostic [] ?? errors.ToArray ();
+
+        if (enumerable.Any ())
         {
-            var errorMessages = string.Join (Environment.NewLine, errors.Select (e => e.ToString ()));
+            string errorMessages = string.Join (Environment.NewLine, enumerable.Select (e => e.ToString ()));
             throw new Exception ("Compilation failed with errors:" + Environment.NewLine + errorMessages);
         }
 
         // Run analyzer
-        var analyzerDiagnostics = await GetAnalyzerDiagnosticsAsync (compilation, _analyzer);
+        ImmutableArray<Diagnostic> analyzerDiagnostics = await GetAnalyzerDiagnosticsAsync (compilation, _analyzer);
 
         Assert.NotEmpty (analyzerDiagnostics);
 
@@ -83,83 +85,87 @@ public sealed class ProjectBuilder
                 throw new InvalidOperationException ("Expected code fix but none was set.");
             }
 
-            var fixedDocument = await ApplyCodeFixAsync (document, analyzerDiagnostics.First (), _codeFix);
+            Document? fixedDocument = await ApplyCodeFixAsync (document, analyzerDiagnostics.First (), _codeFix);
 
-            var formattedDocument = await Formatter.FormatAsync (fixedDocument);
-            var fixedSource = (await formattedDocument.GetTextAsync ()).ToString ();
+            if (fixedDocument is { })
+            {
+                Document formattedDocument = await Formatter.FormatAsync (fixedDocument);
+                string fixedSource = (await formattedDocument.GetTextAsync ()).ToString ();
 
-            Assert.Equal (_expectedFixedCode, fixedSource);
+                Assert.Equal (_expectedFixedCode, fixedSource);
+            }
         }
     }
 
     private static Document CreateDocument (string source)
     {
-        var dd = typeof (Enumerable).GetTypeInfo ().Assembly.Location;
-        var coreDir = Directory.GetParent (dd) ?? throw new Exception ($"Could not find parent directory of dotnet sdk.  Sdk directory was {dd}");
-
-        var workspace = new AdhocWorkspace ();
-        var projectId = ProjectId.CreateNewId ();
-        var documentId = DocumentId.CreateNewId (projectId);
-
-        var references = new List<MetadataReference> ()
-        {
-            MetadataReference.CreateFromFile(typeof(Button).Assembly.Location),
-            MetadataReference.CreateFromFile(typeof(View).Assembly.Location),
-            MetadataReference.CreateFromFile(typeof(System.IO.FileSystemInfo).Assembly.Location),
-            MetadataReference.CreateFromFile(typeof(System.Linq.Enumerable).Assembly.Location),
-            MetadataReference.CreateFromFile(typeof(object).Assembly.Location),
-            MetadataReference.CreateFromFile(typeof(MarshalByValueComponent).Assembly.Location),
-            MetadataReference.CreateFromFile(typeof(ObservableCollection<string>).Assembly.Location),
+        string dd = typeof (Enumerable).GetTypeInfo ().Assembly.Location;
+        DirectoryInfo coreDir = Directory.GetParent (dd) ?? throw new Exception ($"Could not find parent directory of dotnet sdk.  Sdk directory was {dd}");
+
+        AdhocWorkspace workspace = new AdhocWorkspace ();
+        ProjectId projectId = ProjectId.CreateNewId ();
+        DocumentId documentId = DocumentId.CreateNewId (projectId);
+
+        List<MetadataReference> references =
+        [
+            MetadataReference.CreateFromFile (typeof (Button).Assembly.Location),
+            MetadataReference.CreateFromFile (typeof (View).Assembly.Location),
+            MetadataReference.CreateFromFile (typeof (System.IO.FileSystemInfo).Assembly.Location),
+            MetadataReference.CreateFromFile (typeof (System.Linq.Enumerable).Assembly.Location),
+            MetadataReference.CreateFromFile (typeof (object).Assembly.Location),
+            MetadataReference.CreateFromFile (typeof (MarshalByValueComponent).Assembly.Location),
+            MetadataReference.CreateFromFile (typeof (ObservableCollection<string>).Assembly.Location),
 
             // New assemblies required by Terminal.Gui version 2
-            MetadataReference.CreateFromFile(typeof(Size).Assembly.Location),
-            MetadataReference.CreateFromFile(typeof(CanBeNullAttribute).Assembly.Location),
+            MetadataReference.CreateFromFile (typeof (Size).Assembly.Location),
+            MetadataReference.CreateFromFile (typeof (CanBeNullAttribute).Assembly.Location),
+
 
+            MetadataReference.CreateFromFile (Path.Combine (coreDir.FullName, "mscorlib.dll")),
+            MetadataReference.CreateFromFile (Path.Combine (coreDir.FullName, "System.Runtime.dll")),
+            MetadataReference.CreateFromFile (Path.Combine (coreDir.FullName, "System.Collections.dll")),
+            MetadataReference.CreateFromFile (Path.Combine (coreDir.FullName, "System.Data.Common.dll"))
 
-            MetadataReference.CreateFromFile(Path.Combine(coreDir.FullName, "mscorlib.dll")),
-            MetadataReference.CreateFromFile(Path.Combine(coreDir.FullName, "System.Runtime.dll")),
-            MetadataReference.CreateFromFile(Path.Combine(coreDir.FullName, "System.Collections.dll")),
-            MetadataReference.CreateFromFile(Path.Combine(coreDir.FullName, "System.Data.Common.dll")),
             // Add more as necessary
-        };
+        ];
 
 
-        var projectInfo = ProjectInfo.Create (
-                                              projectId,
-                                              VersionStamp.Create (),
-                                              "TestProject",
-                                              "TestAssembly",
-                                              LanguageNames.CSharp,
-                                              compilationOptions: new CSharpCompilationOptions (OutputKind.DynamicallyLinkedLibrary),
-                                              metadataReferences: references);
+        ProjectInfo projectInfo = ProjectInfo.Create (
+                                                      projectId,
+                                                      VersionStamp.Create (),
+                                                      "TestProject",
+                                                      "TestAssembly",
+                                                      LanguageNames.CSharp,
+                                                      compilationOptions: new CSharpCompilationOptions (OutputKind.DynamicallyLinkedLibrary),
+                                                      metadataReferences: references);
 
-        var solution = workspace.CurrentSolution
-                                .AddProject (projectInfo)
-                                .AddDocument (documentId, "Test.cs", SourceText.From (source));
+        Solution solution = workspace.CurrentSolution
+                                     .AddProject (projectInfo)
+                                     .AddDocument (documentId, "Test.cs", SourceText.From (source));
 
         return solution.GetDocument (documentId)!;
     }
 
     private static async Task<ImmutableArray<Diagnostic>> GetAnalyzerDiagnosticsAsync (Compilation compilation, DiagnosticAnalyzer analyzer)
     {
-        var compilationWithAnalyzers = compilation.WithAnalyzers (ImmutableArray.Create (analyzer));
+        CompilationWithAnalyzers compilationWithAnalyzers = compilation.WithAnalyzers ([analyzer]);
         return await compilationWithAnalyzers.GetAnalyzerDiagnosticsAsync ();
     }
 
-    private static async Task<Document> ApplyCodeFixAsync (Document document, Diagnostic diagnostic, CodeFixProvider codeFix)
+    private static async Task<Document?> ApplyCodeFixAsync (Document document, Diagnostic diagnostic, CodeFixProvider codeFix)
     {
-        CodeAction _codeAction = null;
-        var context = new CodeFixContext ((TextDocument)document, diagnostic, (action, _) => _codeAction = action, CancellationToken.None);
+        CodeAction? codeAction = null;
+        var context = new CodeFixContext ((TextDocument)document, diagnostic, (action, _) => codeAction = action, CancellationToken.None);
 
         await codeFix.RegisterCodeFixesAsync (context);
 
-        if (_codeAction == null)
+        if (codeAction == null)
         {
             throw new InvalidOperationException ("Code fix did not register a fix.");
         }
 
-        var operations = await _codeAction.GetOperationsAsync (CancellationToken.None);
-        var solution = operations.OfType<ApplyChangesOperation> ().First ().ChangedSolution;
+        ImmutableArray<CodeActionOperation> operations = await codeAction.GetOperationsAsync (CancellationToken.None);
+        Solution solution = operations.OfType<ApplyChangesOperation> ().First ().ChangedSolution;
         return solution.GetDocument (document.Id);
     }
 }

Terminal.Gui/App/Application.Driver.cs

@@ -1,23 +1,19 @@
 #nullable enable
 
+using System.Diagnostics.CodeAnalysis;
+
 namespace Terminal.Gui.App;
 
 public static partial class Application // Driver abstractions
 {
-    internal static bool _forceFakeConsole;
-
-    /// <summary>Gets the <see cref="IConsoleDriver"/> that has been selected. See also <see cref="ForceDriver"/>.</summary>
-    public static IConsoleDriver? Driver
+    /// <inheritdoc cref="IApplication.Driver"/>
+    public static IDriver? Driver
     {
         get => ApplicationImpl.Instance.Driver;
         internal set => ApplicationImpl.Instance.Driver = value;
     }
 
-    /// <summary>
-    ///     Gets or sets whether <see cref="Application.Driver"/> will be forced to output only the 16 colors defined in
-    ///     <see cref="ColorName16"/>. The default is <see langword="false"/>, meaning 24-bit (TrueColor) colors will be output
-    ///     as long as the selected <see cref="IConsoleDriver"/> supports TrueColor.
-    /// </summary>
+    /// <inheritdoc cref="IApplication.Force16Colors"/>
     [ConfigurationProperty (Scope = typeof (SettingsScope))]
     public static bool Force16Colors
     {
@@ -25,14 +21,7 @@ public static partial class Application // Driver abstractions
         set => ApplicationImpl.Instance.Force16Colors = value;
     }
 
-    /// <summary>
-    ///     Forces the use of the specified driver (one of "fake", "dotnet", "windows", or "unix"). If not
-    ///     specified, the driver is selected based on the platform.
-    /// </summary>
-    /// <remarks>
-    ///     Note, <see cref="Application.Init(IConsoleDriver, string)"/> will override this configuration setting if called
-    ///     with either `driver` or `driverName` specified.
-    /// </remarks>
+    /// <inheritdoc cref="IApplication.ForceDriver"/>
     [ConfigurationProperty (Scope = typeof (SettingsScope))]
     public static string ForceDriver
     {
@@ -40,9 +29,34 @@ public static partial class Application // Driver abstractions
         set => ApplicationImpl.Instance.ForceDriver = value;
     }
 
-    /// <summary>
-    /// Collection of sixel images to write out to screen when updating.
-    /// Only add to this collection if you are sure terminal supports sixel format.
-    /// </summary>
+    /// <inheritdoc cref="IApplication.Sixel"/>
     public static List<SixelToRender> Sixel => ApplicationImpl.Instance.Sixel;
-}
+
+    /// <summary>Gets a list of <see cref="IDriver"/> types and type names that are available.</summary>
+    /// <returns></returns>
+    [RequiresUnreferencedCode ("AOT")]
+    public static (List<Type?>, List<string?>) GetDriverTypes ()
+    {
+        // use reflection to get the list of drivers
+        List<Type?> driverTypes = new ();
+
+        // Only inspect the IDriver assembly
+        var asm = typeof (IDriver).Assembly;
+
+        foreach (Type? type in asm.GetTypes ())
+        {
+            if (typeof (IDriver).IsAssignableFrom (type) && type is { IsAbstract: false, IsClass: true })
+            {
+                driverTypes.Add (type);
+            }
+        }
+
+        List<string?> driverTypeNames = driverTypes
+                                        .Where (d => !typeof (IDriver).IsAssignableFrom (d))
+                                        .Select (d => d!.Name)
+                                        .Union (["dotnet", "windows", "unix", "fake"])
+                                        .ToList ()!;
+
+        return (driverTypes, driverTypeNames);
+    }
+}

Terminal.Gui/App/Application.Keyboard.cs

@@ -4,9 +4,7 @@ namespace Terminal.Gui.App;
 
 public static partial class Application // Keyboard handling
 {
-    /// <summary>
-    /// Static reference to the current <see cref="IApplication"/> <see cref="IKeyboard"/>.
-    /// </summary>
+    /// <inheritdoc cref="IApplication.Keyboard"/>
     public static IKeyboard Keyboard
     {
         get => ApplicationImpl.Instance.Keyboard;
@@ -14,40 +12,14 @@ public static partial class Application // Keyboard handling
                                                            throw new ArgumentNullException(nameof(value));
     }
 
-    /// <summary>
-    ///     Called when the user presses a key (by the <see cref="IConsoleDriver"/>). Raises the cancelable
-    ///     <see cref="KeyDown"/> event, then calls <see cref="View.NewKeyDownEvent"/> on all top level views, and finally
-    ///     if the key was not handled, invokes any Application-scoped <see cref="KeyBindings"/>.
-    /// </summary>
-    /// <remarks>Can be used to simulate key press events.</remarks>
-    /// <param name="key"></param>
-    /// <returns><see langword="true"/> if the key was handled.</returns>
-    public static bool RaiseKeyDownEvent (Key key) => Keyboard.RaiseKeyDownEvent (key);
+    /// <inheritdoc cref="IKeyboard.RaiseKeyDownEvent"/>
+    public static bool RaiseKeyDownEvent (Key key) => ApplicationImpl.Instance.Keyboard.RaiseKeyDownEvent (key);
 
-    /// <summary>
-    ///     Invokes any commands bound at the Application-level to <paramref name="key"/>.
-    /// </summary>
-    /// <param name="key"></param>
-    /// <returns>
-    ///     <see langword="null"/> if no command was found; input processing should continue.
-    ///     <see langword="false"/> if the command was invoked and was not handled (or cancelled); input processing should continue.
-    ///     <see langword="true"/> if the command was invoked the command was handled (or cancelled); input processing should stop.
-    /// </returns>
-    public static bool? InvokeCommandsBoundToKey (Key key) => Keyboard.InvokeCommandsBoundToKey (key);
+    /// <inheritdoc cref="IKeyboard.InvokeCommandsBoundToKey"/>
+    public static bool? InvokeCommandsBoundToKey (Key key) => ApplicationImpl.Instance.Keyboard.InvokeCommandsBoundToKey (key);
 
-    /// <summary>
-    ///     Invokes an Application-bound command.
-    /// </summary>
-    /// <param name="command">The Command to invoke</param>
-    /// <param name="key">The Application-bound Key that was pressed.</param>
-    /// <param name="binding">Describes the binding.</param>
-    /// <returns>
-    ///     <see langword="null"/> if no command was found; input processing should continue.
-    ///     <see langword="false"/> if the command was invoked and was not handled (or cancelled); input processing should continue.
-    ///     <see langword="true"/> if the command was invoked the command was handled (or cancelled); input processing should stop.
-    /// </returns>
-    /// <exception cref="NotSupportedException"></exception>
-    public static bool? InvokeCommand (Command command, Key key, KeyBinding binding) => Keyboard.InvokeCommand (command, key, binding);
+    /// <inheritdoc cref="IKeyboard.InvokeCommand"/>
+    public static bool? InvokeCommand (Command command, Key key, KeyBinding binding) => ApplicationImpl.Instance.Keyboard.InvokeCommand (command, key, binding);
 
     /// <summary>
     ///     Raised when the user presses a key.
@@ -63,29 +35,13 @@ public static partial class Application // Keyboard handling
     /// </remarks>
     public static event EventHandler<Key>? KeyDown
     {
-        add => Keyboard.KeyDown += value;
-        remove => Keyboard.KeyDown -= value;
+        add => ApplicationImpl.Instance.Keyboard.KeyDown += value;
+        remove => ApplicationImpl.Instance.Keyboard.KeyDown -= value;
     }
 
-    /// <summary>
-    ///     Called when the user releases a key (by the <see cref="IConsoleDriver"/>). Raises the cancelable
-    ///     <see cref="KeyUp"/>
-    ///     event
-    ///     then calls <see cref="View.NewKeyUpEvent"/> on all top level views. Called after <see cref="RaiseKeyDownEvent"/>.
-    /// </summary>
-    /// <remarks>Can be used to simulate key release events.</remarks>
-    /// <param name="key"></param>
-    /// <returns><see langword="true"/> if the key was handled.</returns>
-    public static bool RaiseKeyUpEvent (Key key) => Keyboard.RaiseKeyUpEvent (key);
-
-    /// <summary>Gets the Application-scoped key bindings.</summary>
-    public static KeyBindings KeyBindings => Keyboard.KeyBindings;
+    /// <inheritdoc cref="IKeyboard.RaiseKeyUpEvent"/>
+    public static bool RaiseKeyUpEvent (Key key) => ApplicationImpl.Instance.Keyboard.RaiseKeyUpEvent (key);
 
-    internal static void AddKeyBindings ()
-    {
-        if (Keyboard is KeyboardImpl keyboard)
-        {
-            keyboard.AddKeyBindings ();
-        }
-    }
+    /// <inheritdoc cref="IKeyboard.KeyBindings"/>
+    public static KeyBindings KeyBindings => ApplicationImpl.Instance.Keyboard.KeyBindings;
 }

Terminal.Gui/App/Application.Lifecycle.cs

@@ -2,6 +2,10 @@
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
+using Microsoft.VisualBasic;
+using Terminal.Gui.App;
+using Terminal.Gui.Drivers;
+using Terminal.Gui.Views;
 
 namespace Terminal.Gui.App;
 
@@ -11,7 +15,7 @@ public static partial class Application // Lifecycle (Init/Shutdown)
     /// <summary>Initializes a new instance of a Terminal.Gui Application. <see cref="Shutdown"/> must be called when the application is closing.</summary>
     /// <para>Call this method once per instance (or after <see cref="Shutdown"/> has been called).</para>
     /// <para>
-    ///     This function loads the right <see cref="IConsoleDriver"/> for the platform, Creates a <see cref="Toplevel"/>. and
+    ///     This function loads the right <see cref="IDriver"/> for the platform, Creates a <see cref="Toplevel"/>. and
     ///     assigns it to <see cref="Top"/>
     /// </para>
     /// <para>
@@ -22,197 +26,36 @@ public static partial class Application // Lifecycle (Init/Shutdown)
     /// </para>
     /// <para>
     ///     The <see cref="Run{T}"/> function combines
-    ///     <see cref="Init(IConsoleDriver,string)"/> and <see cref="Run(Toplevel, Func{Exception, bool})"/>
+    ///     <see cref="Init(IDriver,string)"/> and <see cref="Run(Toplevel, Func{Exception, bool})"/>
     ///     into a single
     ///     call. An application can use <see cref="Run{T}"/> without explicitly calling
-    ///     <see cref="Init(IConsoleDriver,string)"/>.
+    ///     <see cref="Init(IDriver,string)"/>.
     /// </para>
     /// <param name="driver">
-    ///     The <see cref="IConsoleDriver"/> to use. If neither <paramref name="driver"/> or
+    ///     The <see cref="IDriver"/> to use. If neither <paramref name="driver"/> or
     ///     <paramref name="driverName"/> are specified the default driver for the platform will be used.
     /// </param>
     /// <param name="driverName">
     ///     The short name (e.g. "dotnet", "windows", "unix", or "fake") of the
-    ///     <see cref="IConsoleDriver"/> to use. If neither <paramref name="driver"/> or <paramref name="driverName"/> are
+    ///     <see cref="IDriver"/> to use. If neither <paramref name="driver"/> or <paramref name="driverName"/> are
     ///     specified the default driver for the platform will be used.
     /// </param>
     [RequiresUnreferencedCode ("AOT")]
     [RequiresDynamicCode ("AOT")]
-    public static void Init (IConsoleDriver? driver = null, string? driverName = null)
+    public static void Init (IDriver? driver = null, string? driverName = null)
     {
-        // Check if this is a request for a legacy driver (like FakeDriver)
-        // that isn't supported by the modern application architecture
-        if (driver is null)
-        {
-            var driverNameToCheck = string.IsNullOrWhiteSpace (driverName) ? ForceDriver : driverName;
-            if (!string.IsNullOrEmpty (driverNameToCheck))
-            {
-                (List<Type?> drivers, List<string?> driverTypeNames) = GetDriverTypes ();
-                Type? driverType = drivers.FirstOrDefault (t => t!.Name.Equals (driverNameToCheck, StringComparison.InvariantCultureIgnoreCase));
-                
-                // If it's a legacy IConsoleDriver (not a Facade), use InternalInit which supports legacy drivers
-                if (driverType is { } && !typeof (IConsoleDriverFacade).IsAssignableFrom (driverType))
-                {
-                    InternalInit (driver, driverName);
-                    return;
-                }
-            }
-        }
-        
-        // Otherwise delegate to the ApplicationImpl instance (which uses the modern architecture)
         ApplicationImpl.Instance.Init (driver, driverName ?? ForceDriver);
     }
 
-    internal static int MainThreadId
+    /// <summary>
+    ///     Gets or sets the main thread ID for the application.
+    /// </summary>
+    public static int? MainThreadId
     {
         get => ((ApplicationImpl)ApplicationImpl.Instance).MainThreadId;
         set => ((ApplicationImpl)ApplicationImpl.Instance).MainThreadId = value;
     }
 
-    // INTERNAL function for initializing an app with a Toplevel factory object, driver, and mainloop.
-    //
-    // Called from:
-    //
-    // Init() - When the user wants to use the default Toplevel. calledViaRunT will be false, causing all state to be reset.
-    // Run<T>() - When the user wants to use a custom Toplevel. calledViaRunT will be true, enabling Run<T>() to be called without calling Init first.
-    // Unit Tests - To initialize the app with a custom Toplevel, using the FakeDriver. calledViaRunT will be false, causing all state to be reset.
-    //
-    // calledViaRunT: If false (default) all state will be reset. If true the state will not be reset.
-    [RequiresUnreferencedCode ("AOT")]
-    [RequiresDynamicCode ("AOT")]
-    internal static void InternalInit (
-        IConsoleDriver? driver = null,
-        string? driverName = null,
-        bool calledViaRunT = false
-    )
-    {
-        if (Initialized && driver is null)
-        {
-            return;
-        }
-
-        if (Initialized)
-        {
-            throw new InvalidOperationException ("Init has already been called and must be bracketed by Shutdown.");
-        }
-
-        if (!calledViaRunT)
-        {
-            // Reset all class variables (Application is a singleton).
-            ResetState (ignoreDisposed: true);
-        }
-
-        // For UnitTests
-        if (driver is { })
-        {
-            Driver = driver;
-        }
-
-        // Ignore Configuration for ForceDriver if driverName is specified
-        if (!string.IsNullOrEmpty (driverName))
-        {
-            ForceDriver = driverName;
-        }
-
-        // Check if we need to use a legacy driver (like FakeDriver)
-        // or go through the modern application architecture
-        if (Driver is null)
-        {
-            ApplicationImpl.Instance.Init (driver, driverName);
-            Debug.Assert (Driver is { });
-            return;
-        }
-
-        Debug.Assert (Navigation is null);
-        Navigation = new ();
-
-        Debug.Assert (Popover is null);
-        Popover = new ();
-
-        try
-        {
-            Driver!.Init ();
-            SubscribeDriverEvents ();
-        }
-        catch (InvalidOperationException ex)
-        {
-            // This is a case where the driver is unable to initialize the console.
-            // This can happen if the console is already in use by another process or
-            // if running in unit tests.
-            // In this case, we want to throw a more specific exception.
-            throw new InvalidOperationException (
-                                                 "Unable to initialize the console. This can happen if the console is already in use by another process or in unit tests.",
-                                                 ex
-                                                );
-        }
-
-        SynchronizationContext.SetSynchronizationContext (new MainLoopSyncContext ());
-
-        // TODO: This is probably not needed
-        if (Popover.GetActivePopover () is View popover)
-        {
-            popover.Visible = false;
-        }
-
-        MainThreadId = Thread.CurrentThread.ManagedThreadId;
-        bool init = Initialized = true;
-        InitializedChanged?.Invoke (null, new (init));
-    }
-
-    internal static void SubscribeDriverEvents ()
-    {
-        ArgumentNullException.ThrowIfNull (Driver);
-
-        Driver.SizeChanged += Driver_SizeChanged;
-        Driver.KeyDown += Driver_KeyDown;
-        Driver.KeyUp += Driver_KeyUp;
-        Driver.MouseEvent += Driver_MouseEvent;
-    }
-
-    internal static void UnsubscribeDriverEvents ()
-    {
-        ArgumentNullException.ThrowIfNull (Driver);
-
-        Driver.SizeChanged -= Driver_SizeChanged;
-        Driver.KeyDown -= Driver_KeyDown;
-        Driver.KeyUp -= Driver_KeyUp;
-        Driver.MouseEvent -= Driver_MouseEvent;
-    }
-
-    private static void Driver_SizeChanged (object? sender, SizeChangedEventArgs e) { OnSizeChanging (e); }
-    private static void Driver_KeyDown (object? sender, Key e) { RaiseKeyDownEvent (e); }
-    private static void Driver_KeyUp (object? sender, Key e) { RaiseKeyUpEvent (e); }
-    private static void Driver_MouseEvent (object? sender, MouseEventArgs e) { RaiseMouseEvent (e); }
-
-    /// <summary>Gets a list of <see cref="IConsoleDriver"/> types and type names that are available.</summary>
-    /// <returns></returns>
-    [RequiresUnreferencedCode ("AOT")]
-    public static (List<Type?>, List<string?>) GetDriverTypes ()
-    {
-        // use reflection to get the list of drivers
-        List<Type?> driverTypes = new ();
-
-        // Only inspect the IConsoleDriver assembly
-        var asm = typeof (IConsoleDriver).Assembly;
-
-        foreach (Type? type in asm.GetTypes ())
-        {
-            if (typeof (IConsoleDriver).IsAssignableFrom (type) &&
-                type is { IsAbstract: false, IsClass: true })
-            {
-                driverTypes.Add (type);
-            }
-        }
-
-        List<string?> driverTypeNames = driverTypes
-                                        .Where (d => !typeof (IConsoleDriverFacade).IsAssignableFrom (d))
-                                        .Select (d => d!.Name)
-                                        .Union (["dotnet", "windows", "unix", "fake"])
-                                        .ToList ()!;
-
-        return (driverTypes, driverTypeNames);
-    }
-
     /// <summary>Shutdown an application initialized with <see cref="Init"/>.</summary>
     /// <remarks>
     ///     Shutdown must be called for every call to <see cref="Init"/> or
@@ -236,19 +79,17 @@ public static partial class Application // Lifecycle (Init/Shutdown)
         internal set => ApplicationImpl.Instance.Initialized = value;
     }
 
-    /// <summary>
-    ///     This event is raised after the <see cref="Init"/> and <see cref="Shutdown"/> methods have been called.
-    /// </summary>
-    /// <remarks>
-    ///     Intended to support unit tests that need to know when the application has been initialized.
-    /// </remarks>
-    public static event EventHandler<EventArgs<bool>>? InitializedChanged;
-
-    /// <summary>
-    ///  Raises the <see cref="InitializedChanged"/> event.
-    /// </summary>
-    internal static void OnInitializedChanged (object sender, EventArgs<bool> e)
+    /// <inheritdoc cref="IApplication.InitializedChanged"/>
+    public static event EventHandler<EventArgs<bool>>? InitializedChanged
     {
-        Application.InitializedChanged?.Invoke (sender, e);
+        add => ApplicationImpl.Instance.InitializedChanged += value;
+        remove => ApplicationImpl.Instance.InitializedChanged -= value;
     }
+
+    // IMPORTANT: Ensure all property/fields are reset here. See Init_ResetState_Resets_Properties unit test.
+    // Encapsulate all setting of initial state for Application; Having
+    // this in a function like this ensures we don't make mistakes in
+    // guaranteeing that the state of this singleton is deterministic when Init
+    // starts running and after Shutdown returns.
+    internal static void ResetState (bool ignoreDisposed = false) => ApplicationImpl.Instance?.ResetState (ignoreDisposed);
 }

Terminal.Gui/App/Application.Mouse.cs

@@ -92,10 +92,8 @@ public static partial class Application // Mouse handling
     /// </summary>
     /// <remarks>This method can be used to simulate a mouse event, e.g. in unit tests.</remarks>
     /// <param name="mouseEvent">The mouse event with coordinates relative to the screen.</param>
-    internal static void RaiseMouseEvent (MouseEventArgs mouseEvent) { Mouse.RaiseMouseEvent (mouseEvent); }
-
-    /// <summary>
-    ///     INTERNAL: Clears mouse state during application reset.
-    /// </summary>
-    internal static void ResetMouseState () { Mouse.ResetState (); }
+    internal static void RaiseMouseEvent (MouseEventArgs mouseEvent)
+    {
+        Mouse.RaiseMouseEvent (mouseEvent);
+    }
 }

Terminal.Gui/App/Application.Navigation.cs

@@ -17,16 +17,16 @@ public static partial class Application // Navigation stuff
     [ConfigurationProperty (Scope = typeof (SettingsScope))]
     public static Key NextTabGroupKey
     {
-        get => Keyboard.NextTabGroupKey;
-        set => Keyboard.NextTabGroupKey = value;
+        get => ApplicationImpl.Instance.Keyboard.NextTabGroupKey;
+        set => ApplicationImpl.Instance.Keyboard.NextTabGroupKey = value;
     }
 
     /// <summary>Alternative key to navigate forwards through views. Tab is the primary key.</summary>
     [ConfigurationProperty (Scope = typeof (SettingsScope))]
     public static Key NextTabKey
     {
-        get => Keyboard.NextTabKey;
-        set => Keyboard.NextTabKey = value;
+        get => ApplicationImpl.Instance.Keyboard.NextTabKey;
+        set => ApplicationImpl.Instance.Keyboard.NextTabKey = value;
     }
 
     /// <summary>
@@ -43,23 +43,23 @@ public static partial class Application // Navigation stuff
     /// </remarks>
     public static event EventHandler<Key>? KeyUp
     {
-        add => Keyboard.KeyUp += value;
-        remove => Keyboard.KeyUp -= value;
+        add => ApplicationImpl.Instance.Keyboard.KeyUp += value;
+        remove => ApplicationImpl.Instance.Keyboard.KeyUp -= value;
     }
 
     /// <summary>Alternative key to navigate backwards through views. Shift+Ctrl+Tab is the primary key.</summary>
     [ConfigurationProperty (Scope = typeof (SettingsScope))]
     public static Key PrevTabGroupKey
     {
-        get => Keyboard.PrevTabGroupKey;
-        set => Keyboard.PrevTabGroupKey = value;
+        get => ApplicationImpl.Instance.Keyboard.PrevTabGroupKey;
+        set => ApplicationImpl.Instance.Keyboard.PrevTabGroupKey = value;
     }
 
     /// <summary>Alternative key to navigate backwards through views. Shift+Tab is the primary key.</summary>
     [ConfigurationProperty (Scope = typeof (SettingsScope))]
     public static Key PrevTabKey
     {
-        get => Keyboard.PrevTabKey;
-        set => Keyboard.PrevTabKey = value;
+        get => ApplicationImpl.Instance.Keyboard.PrevTabKey;
+        set => ApplicationImpl.Instance.Keyboard.PrevTabKey = value;
     }
 }

Terminal.Gui/App/Application.Run.cs

@@ -1,5 +1,4 @@
 #nullable enable
-using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 
 namespace Terminal.Gui.App;
@@ -10,498 +9,87 @@ public static partial class Application // Run (Begin -> Run -> Layout/Draw -> E
     [ConfigurationProperty (Scope = typeof (SettingsScope))]
     public static Key QuitKey
     {
-        get => Keyboard.QuitKey;
-        set => Keyboard.QuitKey = value;
+        get => ApplicationImpl.Instance.Keyboard.QuitKey;
+        set => ApplicationImpl.Instance.Keyboard.QuitKey = value;
     }
 
     /// <summary>Gets or sets the key to activate arranging views using the keyboard.</summary>
     [ConfigurationProperty (Scope = typeof (SettingsScope))]
     public static Key ArrangeKey
     {
-        get => Keyboard.ArrangeKey;
-        set => Keyboard.ArrangeKey = value;
+        get => ApplicationImpl.Instance.Keyboard.ArrangeKey;
+        set => ApplicationImpl.Instance.Keyboard.ArrangeKey = value;
     }
 
-    // When `End ()` is called, it is possible `RunState.Toplevel` is a different object than `Top`.
-    // This variable is set in `End` in this case so that `Begin` correctly sets `Top`.
-    private static Toplevel? _cachedRunStateToplevel;
+    /// <inheritdoc cref="IApplication.Begin"/>
+    public static SessionToken Begin (Toplevel toplevel) => ApplicationImpl.Instance.Begin (toplevel);
 
-    /// <summary>
-    ///     Notify that a new <see cref="RunState"/> was created (<see cref="Begin(Toplevel)"/> was called). The token is
-    ///     created in <see cref="Begin(Toplevel)"/> and this event will be fired before that function exits.
-    /// </summary>
-    /// <remarks>
-    ///     If <see cref="EndAfterFirstIteration"/> is <see langword="true"/> callers to <see cref="Begin(Toplevel)"/>
-    ///     must also subscribe to <see cref="NotifyStopRunState"/> and manually dispose of the <see cref="RunState"/> token
-    ///     when the application is done.
-    /// </remarks>
-    public static event EventHandler<RunStateEventArgs>? NotifyNewRunState;
+    /// <inheritdoc cref="IApplication.PositionCursor"/>
+    public static bool PositionCursor () => ApplicationImpl.Instance.PositionCursor ();
 
-    /// <summary>Notify that an existent <see cref="RunState"/> is stopping (<see cref="End(RunState)"/> was called).</summary>
-    /// <remarks>
-    ///     If <see cref="EndAfterFirstIteration"/> is <see langword="true"/> callers to <see cref="Begin(Toplevel)"/>
-    ///     must also subscribe to <see cref="NotifyStopRunState"/> and manually dispose of the <see cref="RunState"/> token
-    ///     when the application is done.
-    /// </remarks>
-    public static event EventHandler<ToplevelEventArgs>? NotifyStopRunState;
-
-    /// <summary>Building block API: Prepares the provided <see cref="Toplevel"/> for execution.</summary>
-    /// <returns>
-    ///     The <see cref="RunState"/> handle that needs to be passed to the <see cref="End(RunState)"/> method upon
-    ///     completion.
-    /// </returns>
-    /// <param name="toplevel">The <see cref="Toplevel"/> to prepare execution for.</param>
-    /// <remarks>
-    ///     This method prepares the provided <see cref="Toplevel"/> for running with the focus, it adds this to the list
-    ///     of <see cref="Toplevel"/>s, lays out the SubViews, focuses the first element, and draws the <see cref="Toplevel"/>
-    ///     in the screen. This is usually followed by executing the <see cref="RunLoop"/> method, and then the
-    ///     <see cref="End(RunState)"/> method upon termination which will undo these changes.
-    /// </remarks>
-    public static RunState Begin (Toplevel toplevel)
-    {
-        ArgumentNullException.ThrowIfNull (toplevel);
-
-        // Ensure the mouse is ungrabbed.
-        if (Mouse.MouseGrabView is { })
-        {
-            Mouse.UngrabMouse ();
-        }
-
-        var rs = new RunState (toplevel);
-
-#if DEBUG_IDISPOSABLE
-        if (View.EnableDebugIDisposableAsserts && Top is { } && toplevel != Top && !TopLevels.Contains (Top))
-        {
-            // This assertion confirm if the Top was already disposed
-            Debug.Assert (Top.WasDisposed);
-            Debug.Assert (Top == _cachedRunStateToplevel);
-        }
-#endif
-
-        lock (TopLevels)
-        {
-            if (Top is { } && toplevel != Top && !TopLevels.Contains (Top))
-            {
-                // If Top was already disposed and isn't on the Toplevels Stack,
-                // clean it up here if is the same as _cachedRunStateToplevel
-                if (Top == _cachedRunStateToplevel)
-                {
-                    Top = null;
-                }
-                else
-                {
-                    // Probably this will never hit
-                    throw new ObjectDisposedException (Top.GetType ().FullName);
-                }
-            }
-
-            // BUGBUG: We should not depend on `Id` internally.
-            // BUGBUG: It is super unclear what this code does anyway.
-            if (string.IsNullOrEmpty (toplevel.Id))
-            {
-                var count = 1;
-                var id = (TopLevels.Count + count).ToString ();
-
-                while (TopLevels.Count > 0 && TopLevels.FirstOrDefault (x => x.Id == id) is { })
-                {
-                    count++;
-                    id = (TopLevels.Count + count).ToString ();
-                }
-
-                toplevel.Id = (TopLevels.Count + count).ToString ();
-
-                TopLevels.Push (toplevel);
-            }
-            else
-            {
-                Toplevel? dup = TopLevels.FirstOrDefault (x => x.Id == toplevel.Id);
-
-                if (dup is null)
-                {
-                    TopLevels.Push (toplevel);
-                }
-            }
-        }
-
-        if (Top is null)
-        {
-            Top = toplevel;
-        }
-
-        if ((Top?.Modal == false && toplevel.Modal)
-            || (Top?.Modal == false && !toplevel.Modal)
-            || (Top?.Modal == true && toplevel.Modal))
-        {
-            if (toplevel.Visible)
-            {
-                if (Top is { HasFocus: true })
-                {
-                    Top.HasFocus = false;
-                }
-
-                // Force leave events for any entered views in the old Top
-                if (GetLastMousePosition () is { })
-                {
-                    RaiseMouseEnterLeaveEvents (GetLastMousePosition ()!.Value, new ());
-                }
-
-                Top?.OnDeactivate (toplevel);
-                Toplevel previousTop = Top!;
-
-                Top = toplevel;
-                Top.OnActivate (previousTop);
-            }
-        }
-
-        // View implements ISupportInitializeNotification which is derived from ISupportInitialize
-        if (!toplevel.IsInitialized)
-        {
-            toplevel.BeginInit ();
-            toplevel.EndInit (); // Calls Layout
-        }
-
-        // Try to set initial focus to any TabStop
-        if (!toplevel.HasFocus)
-        {
-            toplevel.SetFocus ();
-        }
-
-        toplevel.OnLoaded ();
-
-        ApplicationImpl.Instance.LayoutAndDraw (true);
-
-        if (PositionCursor ())
-        {
-            Driver?.UpdateCursor ();
-        }
-
-        NotifyNewRunState?.Invoke (toplevel, new (rs));
-
-        return rs;
-    }
-
-    /// <summary>
-    ///     Calls <see cref="View.PositionCursor"/> on the most focused view.
-    /// </summary>
-    /// <remarks>
-    ///     Does nothing if there is no most focused view.
-    ///     <para>
-    ///         If the most focused view is not visible within it's superview, the cursor will be hidden.
-    ///     </para>
-    /// </remarks>
-    /// <returns><see langword="true"/> if a view positioned the cursor and the position is visible.</returns>
-    internal static bool PositionCursor ()
-    {
-        // Find the most focused view and position the cursor there.
-        View? mostFocused = Navigation?.GetFocused ();
-
-        // If the view is not visible or enabled, don't position the cursor
-        if (mostFocused is null || !mostFocused.Visible || !mostFocused.Enabled)
-        {
-            var current = CursorVisibility.Invisible;
-            Driver?.GetCursorVisibility (out current);
-
-            if (current != CursorVisibility.Invisible)
-            {
-                Driver?.SetCursorVisibility (CursorVisibility.Invisible);
-            }
-
-            return false;
-        }
-
-        // If the view is not visible within it's superview, don't position the cursor
-        Rectangle mostFocusedViewport = mostFocused.ViewportToScreen (mostFocused.Viewport with { Location = Point.Empty });
-
-        Rectangle superViewViewport =
-            mostFocused.SuperView?.ViewportToScreen (mostFocused.SuperView.Viewport with { Location = Point.Empty }) ?? Driver!.Screen;
-
-        if (!superViewViewport.IntersectsWith (mostFocusedViewport))
-        {
-            return false;
-        }
-
-        Point? cursor = mostFocused.PositionCursor ();
-
-        Driver!.GetCursorVisibility (out CursorVisibility currentCursorVisibility);
-
-        if (cursor is { })
-        {
-            // Convert cursor to screen coords
-            cursor = mostFocused.ViewportToScreen (mostFocused.Viewport with { Location = cursor.Value }).Location;
-
-            // If the cursor is not in a visible location in the SuperView, hide it
-            if (!superViewViewport.Contains (cursor.Value))
-            {
-                if (currentCursorVisibility != CursorVisibility.Invisible)
-                {
-                    Driver.SetCursorVisibility (CursorVisibility.Invisible);
-                }
-
-                return false;
-            }
-
-            // Show it
-            if (currentCursorVisibility == CursorVisibility.Invisible)
-            {
-                Driver.SetCursorVisibility (mostFocused.CursorVisibility);
-            }
-
-            return true;
-        }
-
-        if (currentCursorVisibility != CursorVisibility.Invisible)
-        {
-            Driver.SetCursorVisibility (CursorVisibility.Invisible);
-        }
-
-        return false;
-    }
-
-    /// <summary>
-    ///     Runs the application by creating a <see cref="Toplevel"/> object and calling
-    ///     <see cref="Run(Toplevel, Func{Exception, bool})"/>.
-    /// </summary>
-    /// <remarks>
-    ///     <para>Calling <see cref="Init"/> first is not needed as this function will initialize the application.</para>
-    ///     <para>
-    ///         <see cref="Shutdown"/> must be called when the application is closing (typically after Run> has returned) to
-    ///         ensure resources are cleaned up and terminal settings restored.
-    ///     </para>
-    ///     <para>
-    ///         The caller is responsible for disposing the object returned by this method.
-    ///     </para>
-    /// </remarks>
-    /// <returns>The created <see cref="Toplevel"/> object. The caller is responsible for disposing this object.</returns>
+    /// <inheritdoc cref="IApplication.Run(Func{Exception, bool}, string)"/>
     [RequiresUnreferencedCode ("AOT")]
     [RequiresDynamicCode ("AOT")]
-    public static Toplevel Run (Func<Exception, bool>? errorHandler = null, IConsoleDriver? driver = null)
-    {
-        return ApplicationImpl.Instance.Run (errorHandler, driver);
-    }
+    public static Toplevel Run (Func<Exception, bool>? errorHandler = null, string? driver = null) => ApplicationImpl.Instance.Run (errorHandler, driver);
 
-    /// <summary>
-    ///     Runs the application by creating a <see cref="Toplevel"/>-derived object of type <c>T</c> and calling
-    ///     <see cref="Run(Toplevel, Func{Exception, bool})"/>.
-    /// </summary>
-    /// <remarks>
-    ///     <para>Calling <see cref="Init"/> first is not needed as this function will initialize the application.</para>
-    ///     <para>
-    ///         <see cref="Shutdown"/> must be called when the application is closing (typically after Run> has returned) to
-    ///         ensure resources are cleaned up and terminal settings restored.
-    ///     </para>
-    ///     <para>
-    ///         The caller is responsible for disposing the object returned by this method.
-    ///     </para>
-    /// </remarks>
-    /// <param name="errorHandler"></param>
-    /// <param name="driver">
-    ///     The <see cref="IConsoleDriver"/> to use. If not specified the default driver for the platform will
-    ///     be used. Must be <see langword="null"/> if <see cref="Init"/> has already been called.
-    /// </param>
-    /// <returns>The created T object. The caller is responsible for disposing this object.</returns>
+    /// <inheritdoc cref="IApplication.Run{TView}(Func{Exception, bool}, string)"/>
     [RequiresUnreferencedCode ("AOT")]
     [RequiresDynamicCode ("AOT")]
-    public static T Run<T> (Func<Exception, bool>? errorHandler = null, IConsoleDriver? driver = null)
-        where T : Toplevel, new()
-    {
-        return ApplicationImpl.Instance.Run<T> (errorHandler, driver);
-    }
+    public static TView Run<TView> (Func<Exception, bool>? errorHandler = null, string? driver = null)
+        where TView : Toplevel, new() => ApplicationImpl.Instance.Run<TView> (errorHandler, driver);
 
-    /// <summary>Runs the Application using the provided <see cref="Toplevel"/> view.</summary>
-    /// <remarks>
-    ///     <para>
-    ///         This method is used to start processing events for the main application, but it is also used to run other
-    ///         modal <see cref="View"/>s such as <see cref="Dialog"/> boxes.
-    ///     </para>
-    ///     <para>
-    ///         To make a <see cref="Run(Toplevel,System.Func{System.Exception,bool})"/> stop execution, call
-    ///         <see cref="Application.RequestStop"/>.
-    ///     </para>
-    ///     <para>
-    ///         Calling <see cref="Run(Toplevel,System.Func{System.Exception,bool})"/> is equivalent to calling
-    ///         <see cref="Begin(Toplevel)"/>, followed by <see cref="RunLoop(RunState)"/>, and then calling
-    ///         <see cref="End(RunState)"/>.
-    ///     </para>
-    ///     <para>
-    ///         Alternatively, to have a program control the main loop and process events manually, call
-    ///         <see cref="Begin(Toplevel)"/> to set things up manually and then repeatedly call
-    ///         <see cref="RunLoop(RunState)"/> with the wait parameter set to false. By doing this the
-    ///         <see cref="RunLoop(RunState)"/> method will only process any pending events, timers handlers and then
-    ///         return control immediately.
-    ///     </para>
-    ///     <para>
-    ///         When using <see cref="Run{T}"/> or
-    ///         <see cref="Run(System.Func{System.Exception,bool},IConsoleDriver)"/>
-    ///         <see cref="Init"/> will be called automatically.
-    ///     </para>
-    ///     <para>
-    ///         RELEASE builds only: When <paramref name="errorHandler"/> is <see langword="null"/> any exceptions will be
-    ///         rethrown. Otherwise, if <paramref name="errorHandler"/> will be called. If <paramref name="errorHandler"/>
-    ///         returns <see langword="true"/> the <see cref="RunLoop(RunState)"/> will resume; otherwise this method will
-    ///         exit.
-    ///     </para>
-    /// </remarks>
-    /// <param name="view">The <see cref="Toplevel"/> to run as a modal.</param>
-    /// <param name="errorHandler">
-    ///     RELEASE builds only: Handler for any unhandled exceptions (resumes when returns true,
-    ///     rethrows when null).
-    /// </param>
-    public static void Run (Toplevel view, Func<Exception, bool>? errorHandler = null) { ApplicationImpl.Instance.Run (view, errorHandler); }
+    /// <inheritdoc cref="IApplication.Run(Toplevel, Func{Exception, bool})"/>
+    public static void Run (Toplevel view, Func<Exception, bool>? errorHandler = null) => ApplicationImpl.Instance.Run (view, errorHandler);
 
-    /// <summary>Adds a timeout to the application.</summary>
-    /// <remarks>
-    ///     When time specified passes, the callback will be invoked. If the callback returns true, the timeout will be
-    ///     reset, repeating the invocation. If it returns false, the timeout will stop and be removed. The returned value is a
-    ///     token that can be used to stop the timeout by calling <see cref="RemoveTimeout(object)"/>.
-    /// </remarks>
-    public static object? AddTimeout (TimeSpan time, Func<bool> callback) { return ApplicationImpl.Instance.AddTimeout (time, callback); }
+    /// <inheritdoc cref="IApplication.AddTimeout"/>
+    public static object? AddTimeout (TimeSpan time, Func<bool> callback) => ApplicationImpl.Instance.AddTimeout (time, callback);
 
-    /// <summary>Removes a previously scheduled timeout</summary>
-    /// <remarks>The token parameter is the value returned by <see cref="AddTimeout"/>.</remarks>
-    /// Returns
-    /// <see langword="true"/>
-    /// if the timeout is successfully removed; otherwise,
-    /// <see langword="false"/>
-    /// .
-    /// This method also returns
-    /// <see langword="false"/>
-    /// if the timeout is not found.
-    public static bool RemoveTimeout (object token) { return ApplicationImpl.Instance.RemoveTimeout (token); }
-
-    /// <summary>Runs <paramref name="action"/> on the thread that is processing events</summary>
-    /// <param name="action">the action to be invoked on the main processing thread.</param>
-    public static void Invoke (Action action) { ApplicationImpl.Instance.Invoke (action); }
-
-    /// <summary>
-    ///     Causes any Toplevels that need layout to be laid out. Then draws any Toplevels that need display. Only Views that
-    ///     need to be laid out (see <see cref="View.NeedsLayout"/>) will be laid out.
-    ///     Only Views that need to be drawn (see <see cref="View.NeedsDraw"/>) will be drawn.
-    /// </summary>
-    /// <param name="forceRedraw">
-    ///     If <see langword="true"/> the entire View hierarchy will be redrawn. The default is <see langword="false"/> and
-    ///     should only be overriden for testing.
-    /// </param>
-    public static void LayoutAndDraw (bool forceRedraw = false)
-    {
-        ApplicationImpl.Instance.LayoutAndDraw (forceRedraw);
-    }
+    /// <inheritdoc cref="IApplication.RemoveTimeout"/>
+    public static bool RemoveTimeout (object token) => ApplicationImpl.Instance.RemoveTimeout (token);
 
-    /// <summary>This event is raised on each iteration of the main loop.</summary>
-    /// <remarks>See also <see cref="Timeout"/></remarks>
-    public static event EventHandler<IterationEventArgs>? Iteration;
+    /// <inheritdoc cref="IApplication.TimedEvents"/>
+    /// 
+    public static ITimedEvents? TimedEvents => ApplicationImpl.Instance?.TimedEvents;
+    /// <inheritdoc cref="IApplication.Invoke"/>
+    public static void Invoke (Action action) => ApplicationImpl.Instance.Invoke (action);
 
-    /// <summary>
-    ///     Set to true to cause <see cref="End"/> to be called after the first iteration. Set to false (the default) to
-    ///     cause the application to continue running until Application.RequestStop () is called.
-    /// </summary>
-    public static bool EndAfterFirstIteration { get; set; }
+    /// <inheritdoc cref="IApplication.LayoutAndDraw"/>
+    public static void LayoutAndDraw (bool forceRedraw = false) => ApplicationImpl.Instance.LayoutAndDraw (forceRedraw);
 
-    /// <summary>Building block API: Runs the main loop for the created <see cref="Toplevel"/>.</summary>
-    /// <param name="state">The state returned by the <see cref="Begin(Toplevel)"/> method.</param>
-    public static void RunLoop (RunState state)
+    /// <inheritdoc cref="IApplication.StopAfterFirstIteration"/>
+    public static bool StopAfterFirstIteration
     {
-        ArgumentNullException.ThrowIfNull (state);
-        ObjectDisposedException.ThrowIf (state.Toplevel is null, "state");
-
-        var firstIteration = true;
+        get => ApplicationImpl.Instance.StopAfterFirstIteration;
+        set => ApplicationImpl.Instance.StopAfterFirstIteration = value;
+    }
 
-        for (state.Toplevel.Running = true; state.Toplevel?.Running == true;)
-        {
-            if (EndAfterFirstIteration && !firstIteration)
-            {
-                return;
-            }
+    /// <inheritdoc cref="IApplication.RequestStop(Toplevel)"/>
+    public static void RequestStop (Toplevel? top = null) => ApplicationImpl.Instance.RequestStop (top);
 
-            firstIteration = RunIteration (ref state, firstIteration);
-        }
+    /// <inheritdoc cref="IApplication.End"/>
+    public static void End (SessionToken sessionToken) => ApplicationImpl.Instance.End (sessionToken);
 
-        // Run one last iteration to consume any outstanding input events from Driver
-        // This is important for remaining OnKeyUp events.
-        RunIteration (ref state, firstIteration);
-    }
+    /// <inheritdoc cref="IApplication.RaiseIteration"/>
+    internal static void RaiseIteration () => ApplicationImpl.Instance.RaiseIteration ();
 
-    /// <summary>Run one application iteration.</summary>
-    /// <param name="state">The state returned by <see cref="Begin(Toplevel)"/>.</param>
-    /// <param name="firstIteration">
-    ///     Set to <see langword="true"/> if this is the first run loop iteration.
-    /// </param>
-    /// <returns><see langword="false"/> if at least one iteration happened.</returns>
-    public static bool RunIteration (ref RunState state, bool firstIteration = false)
+    /// <inheritdoc cref="IApplication.Iteration"/>
+    public static event EventHandler<IterationEventArgs>? Iteration
     {
-        ApplicationImpl appImpl = (ApplicationImpl)ApplicationImpl.Instance;
-        appImpl.Coordinator?.RunIteration ();
-
-        return false;
+        add => ApplicationImpl.Instance.Iteration += value;
+        remove => ApplicationImpl.Instance.Iteration -= value;
     }
 
-    /// <summary>Stops the provided <see cref="Toplevel"/>, causing or the <paramref name="top"/> if provided.</summary>
-    /// <param name="top">The <see cref="Toplevel"/> to stop.</param>
-    /// <remarks>
-    ///     <para>This will cause <see cref="Application.Run(Toplevel, Func{Exception, bool})"/> to return.</para>
-    ///     <para>
-    ///         Calling <see cref="RequestStop(Toplevel)"/> is equivalent to setting the
-    ///         <see cref="Toplevel.Running"/>
-    ///         property on the currently running <see cref="Toplevel"/> to false.
-    ///     </para>
-    /// </remarks>
-    public static void RequestStop (Toplevel? top = null) { ApplicationImpl.Instance.RequestStop (top); }
-
-    /// <summary>
-    ///     Building block API: completes the execution of a <see cref="Toplevel"/> that was started with
-    ///     <see cref="Begin(Toplevel)"/> .
-    /// </summary>
-    /// <param name="runState">The <see cref="RunState"/> returned by the <see cref="Begin(Toplevel)"/> method.</param>
-    public static void End (RunState runState)
+    /// <inheritdoc cref="IApplication.SessionBegun"/>
+    public static event EventHandler<SessionTokenEventArgs>? SessionBegun
     {
-        ArgumentNullException.ThrowIfNull (runState);
-
-        if (Popover?.GetActivePopover () as View is { Visible: true } visiblePopover)
-        {
-            ApplicationPopover.HideWithQuitCommand (visiblePopover);
-        }
-
-        runState.Toplevel.OnUnloaded ();
-
-        // End the RunState.Toplevel
-        // First, take it off the Toplevel Stack
-        if (TopLevels.TryPop (out Toplevel? topOfStack))
-        {
-            if (topOfStack != runState.Toplevel)
-            {
-                // If the top of the stack is not the RunState.Toplevel then
-                // this call to End is not balanced with the call to Begin that started the RunState
-                throw new ArgumentException ("End must be balanced with calls to Begin");
-            }
-        }
-
-        // Notify that it is closing
-        runState.Toplevel?.OnClosed (runState.Toplevel);
-
-        if (TopLevels.TryPeek (out Toplevel? newTop))
-        {
-            Top = newTop;
-            Top?.SetNeedsDraw ();
-        }
-
-        if (runState.Toplevel is { HasFocus: true })
-        {
-            runState.Toplevel.HasFocus = false;
-        }
-
-        if (Top is { HasFocus: false })
-        {
-            Top.SetFocus ();
-        }
-
-        _cachedRunStateToplevel = runState.Toplevel;
-
-        runState.Toplevel = null;
-        runState.Dispose ();
-
-        LayoutAndDraw (true);
+        add => ApplicationImpl.Instance.SessionBegun += value;
+        remove => ApplicationImpl.Instance.SessionBegun -= value;
     }
-    internal static void RaiseIteration ()
+
+    /// <inheritdoc cref="IApplication.SessionEnded"/>
+    public static event EventHandler<ToplevelEventArgs>? SessionEnded
     {
-        Iteration?.Invoke (null, new ());
+        add => ApplicationImpl.Instance.SessionEnded += value;
+        remove => ApplicationImpl.Instance.SessionEnded -= value;
     }
 }

Terminal.Gui/App/Application.Screen.cs

@@ -4,62 +4,23 @@ namespace Terminal.Gui.App;
 
 public static partial class Application // Screen related stuff; intended to hide Driver details
 {
-    /// <summary>
-    ///     Gets or sets the size of the screen. By default, this is the size of the screen as reported by the <see cref="IConsoleDriver"/>.
-    /// </summary>
-    /// <remarks>
-    /// <para>
-    ///     If the <see cref="IConsoleDriver"/> has not been initialized, this will return a default size of 2048x2048; useful for unit tests.
-    /// </para>
-    /// </remarks>
+    /// <inheritdoc cref="IApplication.Screen"/>
+
     public static Rectangle Screen
     {
         get => ApplicationImpl.Instance.Screen;
         set => ApplicationImpl.Instance.Screen = value;
     }
 
-    /// <summary>Invoked when the terminal's size changed. The new size of the terminal is provided.</summary>
-    /// <remarks>
-    ///     Event handlers can set <see cref="SizeChangedEventArgs.Cancel"/> to <see langword="true"/> to prevent
-    ///     <see cref="Application"/> from changing it's size to match the new terminal size.
-    /// </remarks>
-    public static event EventHandler<SizeChangedEventArgs>? SizeChanging;
-
-    /// <summary>
-    ///     Called when the application's size changes. Sets the size of all <see cref="Toplevel"/>s and fires the
-    ///     <see cref="SizeChanging"/> event.
-    /// </summary>
-    /// <param name="args">The new size.</param>
-    /// <returns><see lanword="true"/>if the size was changed.</returns>
-    public static bool OnSizeChanging (SizeChangedEventArgs args)
+    /// <inheritdoc cref="IApplication.ScreenChanged"/>
+    public static event EventHandler<EventArgs<Rectangle>>? ScreenChanged
     {
-        SizeChanging?.Invoke (null, args);
-
-        if (args.Cancel || args.Size is null)
-        {
-            return false;
-        }
-
-        Screen = new (Point.Empty, args.Size.Value);
-
-        foreach (Toplevel t in TopLevels)
-        {
-            t.OnSizeChanging (new (args.Size));
-            t.SetNeedsLayout ();
-        }
-
-        LayoutAndDraw (true);
-
-        return true;
+        add => ApplicationImpl.Instance.ScreenChanged += value;
+        remove => ApplicationImpl.Instance.ScreenChanged -= value;
     }
 
-    /// <summary>
-    ///     Gets or sets whether the screen will be cleared, and all Views redrawn, during the next Application iteration.
-    /// </summary>
-    /// <remarks>
-    ///     This is typical set to true when a View's <see cref="View.Frame"/> changes and that view has no
-    ///     SuperView (e.g. when <see cref="Application.Top"/> is moved or resized.
-    /// </remarks>
+    /// <inheritdoc cref="IApplication.ClearScreenNextIteration"/>
+
     internal static bool ClearScreenNextIteration
     {
         get => ApplicationImpl.Instance.ClearScreenNextIteration;

Terminal.Gui/App/Application.Toplevel.cs

@@ -5,10 +5,8 @@ namespace Terminal.Gui.App;
 
 public static partial class Application // Toplevel handling
 {
-    // BUGBUG: Technically, this is not the full lst of TopLevels. There be dragons here, e.g. see how Toplevel.Id is used. What
-
-    /// <summary>Holds the stack of TopLevel views.</summary>
-    internal static ConcurrentStack<Toplevel> TopLevels => ApplicationImpl.Instance.TopLevels;
+    /// <inheritdoc cref="IApplication.TopLevels"/>
+    public static ConcurrentStack<Toplevel> TopLevels => ApplicationImpl.Instance.TopLevels;
 
     /// <summary>The <see cref="Toplevel"/> that is currently active.</summary>
     /// <value>The top.</value>

Terminal.Gui/App/Application.cd

@@ -36,19 +36,19 @@
       <FileName>App\MainLoopSyncContext.cs</FileName>
     </TypeIdentifier>
   </Class>
-  <Class Name="Terminal.Gui.App.RunState" Collapsed="true" BaseTypeListCollapsed="true">
+  <Class Name="Terminal.Gui.App.SessionToken" Collapsed="true" BaseTypeListCollapsed="true">
     <Position X="15.25" Y="4" Width="1.5" />
     <TypeIdentifier>
       <HashCode>AAAAAAAAACACAgAAAAAAAAAAAAAAAAACQAAAAAAAAAA=</HashCode>
-      <FileName>App\RunState.cs</FileName>
+      <FileName>App\SessionToken.cs</FileName>
     </TypeIdentifier>
     <Lollipop Position="0.2" Collapsed="true" />
   </Class>
-  <Class Name="Terminal.Gui.App.RunStateEventArgs" Collapsed="true">
+  <Class Name="Terminal.Gui.App.SessionTokenEventArgs" Collapsed="true">
     <Position X="17" Y="4" Width="2" />
     <TypeIdentifier>
       <HashCode>AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAA=</HashCode>
-      <FileName>App\RunStateEventArgs.cs</FileName>
+      <FileName>App\SessionTokenEventArgs.cs</FileName>
     </TypeIdentifier>
   </Class>
   <Class Name="Terminal.Gui.App.Timeout" Collapsed="true">

Terminal.Gui/App/Application.cs

@@ -39,18 +39,6 @@ namespace Terminal.Gui.App;
 /// <remarks></remarks>
 public static partial class Application
 {
-    /// <summary>Gets all cultures supported by the application without the invariant language.</summary>
-    public static List<CultureInfo>? SupportedCultures { get; private set; } = GetSupportedCultures ();
-
-
-    /// <summary>
-    /// <para>
-    /// Handles recurring events. These are invoked on the main UI thread - allowing for
-    /// safe updates to <see cref="View"/> instances.
-    /// </para>
-    /// </summary>
-    public static ITimedEvents? TimedEvents => ApplicationImpl.Instance?.TimedEvents;
-
     /// <summary>
     /// Maximum number of iterations of the main loop (and hence draws)
     /// to allow to occur per second. Defaults to <see cref="DefaultMaximumIterationsPerSecond"/>> which is a 40ms sleep
@@ -71,7 +59,7 @@ public static partial class Application
     /// <returns>A string representation of the Application </returns>
     public new static string ToString ()
     {
-        IConsoleDriver? driver = Driver;
+        IDriver? driver = Driver;
 
         if (driver is null)
         {
@@ -82,11 +70,11 @@ public static partial class Application
     }
 
     /// <summary>
-    ///     Gets a string representation of the Application rendered by the provided <see cref="IConsoleDriver"/>.
+    ///     Gets a string representation of the Application rendered by the provided <see cref="IDriver"/>.
     /// </summary>
     /// <param name="driver">The driver to use to render the contents.</param>
     /// <returns>A string representation of the Application </returns>
-    public static string ToString (IConsoleDriver? driver)
+    public static string ToString (IDriver? driver)
     {
         if (driver is null)
         {
@@ -129,6 +117,10 @@ public static partial class Application
         return sb.ToString ();
     }
 
+    /// <summary>Gets all cultures supported by the application without the invariant language.</summary>
+    public static List<CultureInfo>? SupportedCultures { get; private set; } = GetSupportedCultures ();
+
+
     internal static List<CultureInfo> GetAvailableCulturesFromEmbeddedResources ()
     {
         ResourceManager rm = new (typeof (Strings));
@@ -171,100 +163,4 @@ public static partial class Application
         // It's called from a self-contained single-file and get available cultures from the embedded resources strings.
         return GetAvailableCulturesFromEmbeddedResources ();
     }
-
-    // IMPORTANT: Ensure all property/fields are reset here. See Init_ResetState_Resets_Properties unit test.
-    // Encapsulate all setting of initial state for Application; Having
-    // this in a function like this ensures we don't make mistakes in
-    // guaranteeing that the state of this singleton is deterministic when Init
-    // starts running and after Shutdown returns.
-    internal static void ResetState (bool ignoreDisposed = false)
-    {
-        // Shutdown is the bookend for Init. As such it needs to clean up all resources
-        // Init created. Apps that do any threading will need to code defensively for this.
-        // e.g. see Issue #537
-        foreach (Toplevel? t in TopLevels)
-        {
-            t!.Running = false;
-        }
-
-        if (Popover?.GetActivePopover () is View popover)
-        {
-            // This forcefully closes the popover; invoking Command.Quit would be more graceful
-            // but since this is shutdown, doing this is ok.
-            popover.Visible = false;
-        }
-
-        Popover?.Dispose ();
-        Popover = null;
-
-        TopLevels.Clear ();
-#if DEBUG_IDISPOSABLE
-
-        // Don't dispose the Top. It's up to caller dispose it
-        if (View.EnableDebugIDisposableAsserts && !ignoreDisposed && Top is { })
-        {
-            Debug.Assert (Top.WasDisposed, $"Title = {Top.Title}, Id = {Top.Id}");
-
-            // If End wasn't called _cachedRunStateToplevel may be null
-            if (_cachedRunStateToplevel is { })
-            {
-                Debug.Assert (_cachedRunStateToplevel.WasDisposed);
-                Debug.Assert (_cachedRunStateToplevel == Top);
-            }
-        }
-#endif
-        Top = null;
-        _cachedRunStateToplevel = null;
-
-        MainThreadId = -1;
-        Iteration = null;
-        EndAfterFirstIteration = false;
-        ClearScreenNextIteration = false;
-
-        // Driver stuff
-        if (Driver is { })
-        {
-            UnsubscribeDriverEvents ();
-            Driver?.End ();
-            Driver = null;
-        }
-
-        // Reset Screen to null so it will be recalculated on next access
-        // Note: ApplicationImpl.Shutdown() also calls ResetScreen() before calling this method
-        // to avoid potential circular reference issues. Calling it twice is harmless.
-        if (ApplicationImpl.Instance is ApplicationImpl impl)
-        {
-            impl.ResetScreen ();
-        }
-
-        // Don't reset ForceDriver; it needs to be set before Init is called.
-        //ForceDriver = string.Empty;
-        //Force16Colors = false;
-        _forceFakeConsole = false;
-
-        // Run State stuff
-        NotifyNewRunState = null;
-        NotifyStopRunState = null;
-        // Mouse and Keyboard will be lazy-initialized in ApplicationImpl on next access
-        Initialized = false;
-
-        // Mouse
-        // Do not clear _lastMousePosition; Popovers require it to stay set with
-        // last mouse pos.
-        //_lastMousePosition = null;
-        CachedViewsUnderMouse.Clear ();
-        ResetMouseState ();
-
-        // Keyboard events and bindings are now managed by the Keyboard instance
-
-        SizeChanging = null;
-
-        Navigation = null;
-
-        // Reset synchronization context to allow the user to run async/await,
-        // as the main loop has been ended, the synchronization context from
-        // gui.cs does no longer process any callbacks. See #1084 for more details:
-        // (https://github.com/gui-cs/Terminal.Gui/issues/1084).
-        SynchronizationContext.SetSynchronizationContext (null);
-    }
 }

Terminal.Gui/App/ApplicationImpl.Driver.cs

@@ -0,0 +1,176 @@
+#nullable enable
+using System.Collections.Concurrent;
+
+namespace Terminal.Gui.App;
+
+public partial class ApplicationImpl
+{
+    /// <inheritdoc/>
+    public IDriver? Driver { get; set; }
+
+    /// <inheritdoc/>
+    public bool Force16Colors { get; set; }
+
+    /// <inheritdoc/>
+    public string ForceDriver { get; set; } = string.Empty;
+
+    /// <inheritdoc/>
+    public List<SixelToRender> Sixel { get; } = new ();
+
+    /// <summary>
+    ///     Creates the appropriate <see cref="IDriver"/> based on platform and driverName.
+    /// </summary>
+    /// <param name="driverName"></param>
+    /// <returns></returns>
+    /// <exception cref="Exception"></exception>
+    /// <exception cref="InvalidOperationException"></exception>
+    private void CreateDriver (string? driverName)
+    {
+        PlatformID p = Environment.OSVersion.Platform;
+
+        // Check component factory type first - this takes precedence over driverName
+        bool factoryIsWindows = _componentFactory is IComponentFactory<WindowsConsole.InputRecord>;
+        bool factoryIsDotNet = _componentFactory is IComponentFactory<ConsoleKeyInfo>;
+        bool factoryIsUnix = _componentFactory is IComponentFactory<char>;
+        bool factoryIsFake = _componentFactory is IComponentFactory<ConsoleKeyInfo>;
+
+        // Then check driverName
+        bool nameIsWindows = driverName?.Contains ("win", StringComparison.OrdinalIgnoreCase) ?? false;
+        bool nameIsDotNet = driverName?.Contains ("dotnet", StringComparison.OrdinalIgnoreCase) ?? false;
+        bool nameIsUnix = driverName?.Contains ("unix", StringComparison.OrdinalIgnoreCase) ?? false;
+        bool nameIsFake = driverName?.Contains ("fake", StringComparison.OrdinalIgnoreCase) ?? false;
+
+        // Decide which driver to use - component factory type takes priority
+        if (factoryIsFake || (!factoryIsWindows && !factoryIsDotNet && !factoryIsUnix && nameIsFake))
+        {
+            Coordinator = CreateSubcomponents (() => new FakeComponentFactory ());
+            _driverName = "fake";
+        }
+        else if (factoryIsWindows || (!factoryIsDotNet && !factoryIsUnix && nameIsWindows))
+        {
+            Coordinator = CreateSubcomponents (() => new WindowsComponentFactory ());
+            _driverName = "windows";
+        }
+        else if (factoryIsDotNet || (!factoryIsWindows && !factoryIsUnix && nameIsDotNet))
+        {
+            Coordinator = CreateSubcomponents (() => new NetComponentFactory ());
+            _driverName = "dotnet";
+        }
+        else if (factoryIsUnix || (!factoryIsWindows && !factoryIsDotNet && nameIsUnix))
+        {
+            Coordinator = CreateSubcomponents (() => new UnixComponentFactory ());
+            _driverName = "unix";
+        }
+        else if (p == PlatformID.Win32NT || p == PlatformID.Win32S || p == PlatformID.Win32Windows)
+        {
+            Coordinator = CreateSubcomponents (() => new WindowsComponentFactory ());
+            _driverName = "windows";
+        }
+        else if (p == PlatformID.Unix)
+        {
+            Coordinator = CreateSubcomponents (() => new UnixComponentFactory ());
+            _driverName = "unix";
+        }
+        else
+        {
+            Logging.Information($"Falling back to dotnet driver.");
+            Coordinator = CreateSubcomponents (() => new NetComponentFactory ());
+            _driverName = "dotnet";
+        }
+
+        Logging.Trace ($"Created Subcomponents: {Coordinator}");
+
+        Coordinator.StartInputTaskAsync ().Wait ();
+
+        if (Driver == null)
+        {
+            throw new ("Driver was null even after booting MainLoopCoordinator");
+        }
+    }
+
+    private readonly IComponentFactory? _componentFactory;
+
+    /// <summary>
+    ///     INTERNAL: Gets or sets the main loop coordinator that orchestrates the application's event processing,
+    ///     input handling, and rendering pipeline.
+    /// </summary>
+    /// <remarks>
+    ///     <para>
+    ///         The <see cref="IMainLoopCoordinator"/> is the central component responsible for:
+    ///         <list type="bullet">
+    ///             <item>Managing the platform-specific input thread that reads from the console</item>
+    ///             <item>Coordinating the main application loop via <see cref="IMainLoopCoordinator.RunIteration"/></item>
+    ///             <item>Processing queued input events and translating them to Terminal.Gui events</item>
+    ///             <item>Managing the <see cref="ApplicationMainLoop{TInputRecord}"/> that handles rendering</item>
+    ///             <item>Executing scheduled timeouts and callbacks via <see cref="ITimedEvents"/></item>
+    ///         </list>
+    ///     </para>
+    ///     <para>
+    ///         The coordinator is created in <see cref="CreateDriver"/> based on the selected driver
+    ///         (Windows, Unix, .NET, or Fake) and is started by calling
+    ///         <see cref="IMainLoopCoordinator.StartInputTaskAsync"/>.
+    ///     </para>
+    /// </remarks>
+    internal IMainLoopCoordinator? Coordinator { get; private set; }
+
+    /// <summary>
+    ///     INTERNAL: Creates a <see cref="MainLoopCoordinator{TInputRecord}"/> with the appropriate component factory
+    ///     for the specified input record type.
+    /// </summary>
+    /// <typeparam name="TInputRecord">
+    ///     Platform-specific input type: <see cref="ConsoleKeyInfo"/> (.NET/Fake),
+    ///     <see cref="WindowsConsole.InputRecord"/> (Windows), or <see cref="char"/> (Unix).
+    /// </typeparam>
+    /// <param name="fallbackFactory">
+    ///     Factory function to create the component factory if <see cref="_componentFactory"/>
+    ///     is not of type <see cref="IComponentFactory{TInputRecord}"/>.
+    /// </param>
+    /// <returns>
+    ///     A <see cref="MainLoopCoordinator{TInputRecord}"/> configured with the input queue,
+    ///     main loop, timed events, and selected component factory.
+    /// </returns>
+    private IMainLoopCoordinator CreateSubcomponents<TInputRecord> (Func<IComponentFactory<TInputRecord>> fallbackFactory) where TInputRecord : struct
+    {
+        ConcurrentQueue<TInputRecord> inputQueue = new ();
+        ApplicationMainLoop<TInputRecord> loop = new ();
+
+        IComponentFactory<TInputRecord> cf;
+
+        if (_componentFactory is IComponentFactory<TInputRecord> typedFactory)
+        {
+            cf = typedFactory;
+        }
+        else
+        {
+            cf = fallbackFactory ();
+        }
+
+        return new MainLoopCoordinator<TInputRecord> (_timedEvents, inputQueue, loop, cf);
+    }
+
+    internal void SubscribeDriverEvents ()
+    {
+        ArgumentNullException.ThrowIfNull (Driver);
+
+        Driver.SizeChanged += Driver_SizeChanged;
+        Driver.KeyDown += Driver_KeyDown;
+        Driver.KeyUp += Driver_KeyUp;
+        Driver.MouseEvent += Driver_MouseEvent;
+    }
+
+    internal void UnsubscribeDriverEvents ()
+    {
+        ArgumentNullException.ThrowIfNull (Driver);
+
+        Driver.SizeChanged -= Driver_SizeChanged;
+        Driver.KeyDown -= Driver_KeyDown;
+        Driver.KeyUp -= Driver_KeyUp;
+        Driver.MouseEvent -= Driver_MouseEvent;
+    }
+
+    private void Driver_KeyDown (object? sender, Key e) { Keyboard?.RaiseKeyDownEvent (e); }
+
+    private void Driver_KeyUp (object? sender, Key e) { Keyboard?.RaiseKeyUpEvent (e); }
+
+    private void Driver_MouseEvent (object? sender, MouseEventArgs e) { Mouse?.RaiseMouseEvent (e); }
+}

Terminal.Gui/App/ApplicationImpl.Lifecycle.cs

@@ -0,0 +1,251 @@
+#nullable enable
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+
+namespace Terminal.Gui.App;
+
+public partial class ApplicationImpl
+{
+    /// <inheritdoc/>
+    public bool Initialized { get; set; }
+
+    /// <inheritdoc/>
+    public event EventHandler<EventArgs<bool>>? InitializedChanged;
+
+    /// <inheritdoc/>
+    [RequiresUnreferencedCode ("AOT")]
+    [RequiresDynamicCode ("AOT")]
+    public void Init (IDriver? driver = null, string? driverName = null)
+    {
+        if (Initialized)
+        {
+            Logging.Error ("Init called multiple times without shutdown, aborting.");
+
+            throw new InvalidOperationException ("Init called multiple times without Shutdown");
+        }
+
+        if (!string.IsNullOrWhiteSpace (driverName))
+        {
+            _driverName = driverName;
+        }
+
+        if (string.IsNullOrWhiteSpace (_driverName))
+        {
+            _driverName = ForceDriver;
+        }
+
+        Debug.Assert (Navigation is null);
+        Navigation = new ();
+
+        Debug.Assert (Popover is null);
+        Popover = new ();
+
+        // Preserve existing keyboard settings if they exist
+        bool hasExistingKeyboard = _keyboard is { };
+        Key existingQuitKey = _keyboard?.QuitKey ?? Key.Esc;
+        Key existingArrangeKey = _keyboard?.ArrangeKey ?? Key.F5.WithCtrl;
+        Key existingNextTabKey = _keyboard?.NextTabKey ?? Key.Tab;
+        Key existingPrevTabKey = _keyboard?.PrevTabKey ?? Key.Tab.WithShift;
+        Key existingNextTabGroupKey = _keyboard?.NextTabGroupKey ?? Key.F6;
+        Key existingPrevTabGroupKey = _keyboard?.PrevTabGroupKey ?? Key.F6.WithShift;
+
+        // Reset keyboard to ensure fresh state with default bindings
+        _keyboard = new KeyboardImpl { Application = this };
+
+        // Restore previously set keys if they existed and were different from defaults
+        if (hasExistingKeyboard)
+        {
+            _keyboard.QuitKey = existingQuitKey;
+            _keyboard.ArrangeKey = existingArrangeKey;
+            _keyboard.NextTabKey = existingNextTabKey;
+            _keyboard.PrevTabKey = existingPrevTabKey;
+            _keyboard.NextTabGroupKey = existingNextTabGroupKey;
+            _keyboard.PrevTabGroupKey = existingPrevTabGroupKey;
+        }
+
+        CreateDriver (driverName ?? _driverName);
+        Screen = Driver!.Screen;
+        Initialized = true;
+
+        RaiseInitializedChanged (this, new (true));
+        SubscribeDriverEvents ();
+
+        SynchronizationContext.SetSynchronizationContext (new ());
+        MainThreadId = Thread.CurrentThread.ManagedThreadId;
+    }
+
+    /// <summary>Shutdown an application initialized with <see cref="Init"/>.</summary>
+    public void Shutdown ()
+    {
+        // Stop the coordinator if running
+        Coordinator?.Stop ();
+
+        // Capture state before cleanup
+        bool wasInitialized = Initialized;
+
+#if DEBUG
+
+        // Check that all Application events have no remaining subscribers BEFORE clearing them
+        // Only check if we were actually initialized
+        if (wasInitialized)
+        {
+            AssertNoEventSubscribers (nameof (Iteration), Iteration);
+            AssertNoEventSubscribers (nameof (SessionBegun), SessionBegun);
+            AssertNoEventSubscribers (nameof (SessionEnded), SessionEnded);
+            AssertNoEventSubscribers (nameof (ScreenChanged), ScreenChanged);
+
+            //AssertNoEventSubscribers (nameof (InitializedChanged), InitializedChanged);
+        }
+#endif
+
+        // Clean up all application state (including sync context)
+        // ResetState handles the case where Initialized is false
+        ResetState ();
+
+        // Configuration manager diagnostics
+        ConfigurationManager.PrintJsonErrors ();
+
+        // Raise the initialized changed event to notify shutdown
+        if (wasInitialized)
+        {
+            bool init = Initialized; // Will be false after ResetState
+            RaiseInitializedChanged (this, new (in init));
+        }
+
+        // Clear the event to prevent memory leaks
+        InitializedChanged = null;
+
+        // Create a new lazy instance for potential future Init
+        _lazyInstance = new (() => new ApplicationImpl ());
+    }
+
+#if DEBUG
+    /// <summary>
+    ///     DEBUG ONLY: Asserts that an event has no remaining subscribers.
+    /// </summary>
+    /// <param name="eventName">The name of the event for diagnostic purposes.</param>
+    /// <param name="eventDelegate">The event delegate to check.</param>
+    private static void AssertNoEventSubscribers (string eventName, Delegate? eventDelegate)
+    {
+        if (eventDelegate is null)
+        {
+            return;
+        }
+
+        Delegate [] subscribers = eventDelegate.GetInvocationList ();
+
+        if (subscribers.Length > 0)
+        {
+            string subscriberInfo = string.Join (
+                                                 ", ",
+                                                 subscribers.Select (d => $"{d.Method.DeclaringType?.Name}.{d.Method.Name}"
+                                                                    )
+                                                );
+
+            Debug.Fail (
+                        $"Application.{eventName} has {subscribers.Length} remaining subscriber(s) after Shutdown: {subscriberInfo}"
+                       );
+        }
+    }
+#endif
+
+    /// <inheritdoc/>
+    public void ResetState (bool ignoreDisposed = false)
+    {
+        // Shutdown is the bookend for Init. As such it needs to clean up all resources
+        // Init created. Apps that do any threading will need to code defensively for this.
+        // e.g. see Issue #537
+
+        // === 1. Stop all running toplevels ===
+        foreach (Toplevel? t in TopLevels)
+        {
+            t!.Running = false;
+        }
+
+        // === 2. Close and dispose popover ===
+        if (Popover?.GetActivePopover () is View popover)
+        {
+            // This forcefully closes the popover; invoking Command.Quit would be more graceful
+            // but since this is shutdown, doing this is ok.
+            popover.Visible = false;
+        }
+
+        Popover?.Dispose ();
+        Popover = null;
+
+        // === 3. Clean up toplevels ===
+        TopLevels.Clear ();
+
+#if DEBUG_IDISPOSABLE
+
+        // Don't dispose the Top. It's up to caller dispose it
+        if (View.EnableDebugIDisposableAsserts && !ignoreDisposed && Top is { })
+        {
+            Debug.Assert (Top.WasDisposed, $"Title = {Top.Title}, Id = {Top.Id}");
+
+            // If End wasn't called _CachedSessionTokenToplevel may be null
+            if (CachedSessionTokenToplevel is { })
+            {
+                Debug.Assert (CachedSessionTokenToplevel.WasDisposed);
+                Debug.Assert (CachedSessionTokenToplevel == Top);
+            }
+        }
+#endif
+
+        Top = null;
+        CachedSessionTokenToplevel = null;
+
+        // === 4. Clean up driver ===
+        if (Driver is { })
+        {
+            UnsubscribeDriverEvents ();
+            Driver?.End ();
+            Driver = null;
+        }
+
+        // Reset screen
+        ResetScreen ();
+        _screen = null;
+
+        // === 5. Clear run state ===
+        Iteration = null;
+        SessionBegun = null;
+        SessionEnded = null;
+        StopAfterFirstIteration = false;
+        ClearScreenNextIteration = false;
+
+        // === 6. Reset input systems ===
+        // Mouse and Keyboard will be lazy-initialized on next access
+        _mouse = null;
+        _keyboard = null;
+        Mouse.ResetState ();
+
+        // === 7. Clear navigation and screen state ===
+        ScreenChanged = null;
+        Navigation = null;
+
+        // === 8. Reset initialization state ===
+        Initialized = false;
+        MainThreadId = null;
+
+        // === 9. Clear graphics ===
+        Sixel.Clear ();
+
+        // === 10. Reset synchronization context ===
+        // IMPORTANT: Always reset sync context, even if not initialized
+        // This ensures cleanup works correctly even if Shutdown is called without Init
+        // Reset synchronization context to allow the user to run async/await,
+        // as the main loop has been ended, the synchronization context from
+        // gui.cs does no longer process any callbacks. See #1084 for more details:
+        // (https://github.com/gui-cs/Terminal.Gui/issues/1084).
+        SynchronizationContext.SetSynchronizationContext (null);
+
+        // Note: ForceDriver and Force16Colors are NOT reset; 
+        // they need to persist across Init/Shutdown cycles
+    }
+
+    /// <summary>
+    ///     Raises the <see cref="InitializedChanged"/> event.
+    /// </summary>
+    internal void RaiseInitializedChanged (object sender, EventArgs<bool> e) { InitializedChanged?.Invoke (sender, e); }
+}

Terminal.Gui/App/ApplicationImpl.Run.cs

@@ -0,0 +1,347 @@
+#nullable enable
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+
+namespace Terminal.Gui.App;
+
+public partial class ApplicationImpl
+{
+    /// <summary>
+    ///     INTERNAL: Gets or sets the managed thread ID of the application's main UI thread, which is set during
+    ///     <see cref="Init"/> and used to determine if code is executing on the main thread.
+    /// </summary>
+    /// <value>
+    ///     The managed thread ID of the main UI thread, or <see langword="null"/> if the application is not initialized.
+    /// </value>
+    internal int? MainThreadId { get; set; }
+
+    #region Begin->Run->Stop->End
+
+    /// <inheritdoc/>
+    public event EventHandler<SessionTokenEventArgs>? SessionBegun;
+
+    /// <inheritdoc/>
+    public event EventHandler<ToplevelEventArgs>? SessionEnded;
+
+    /// <inheritdoc/>
+    public SessionToken Begin (Toplevel toplevel)
+    {
+        ArgumentNullException.ThrowIfNull (toplevel);
+
+        // Ensure the mouse is ungrabbed.
+        if (Mouse.MouseGrabView is { })
+        {
+            Mouse.UngrabMouse ();
+        }
+
+        var rs = new SessionToken (toplevel);
+
+#if DEBUG_IDISPOSABLE
+        if (View.EnableDebugIDisposableAsserts && Top is { } && toplevel != Top && !TopLevels.Contains (Top))
+        {
+            // This assertion confirm if the Top was already disposed
+            Debug.Assert (Top.WasDisposed);
+            Debug.Assert (Top == CachedSessionTokenToplevel);
+        }
+#endif
+
+        lock (TopLevels)
+        {
+            if (Top is { } && toplevel != Top && !TopLevels.Contains (Top))
+            {
+                // If Top was already disposed and isn't on the Toplevels Stack,
+                // clean it up here if is the same as _CachedSessionTokenToplevel
+                if (Top == CachedSessionTokenToplevel)
+                {
+                    Top = null;
+                }
+                else
+                {
+                    // Probably this will never hit
+                    throw new ObjectDisposedException (Top.GetType ().FullName);
+                }
+            }
+
+            // BUGBUG: We should not depend on `Id` internally.
+            // BUGBUG: It is super unclear what this code does anyway.
+            if (string.IsNullOrEmpty (toplevel.Id))
+            {
+                var count = 1;
+                var id = (TopLevels.Count + count).ToString ();
+
+                while (TopLevels.Count > 0 && TopLevels.FirstOrDefault (x => x.Id == id) is { })
+                {
+                    count++;
+                    id = (TopLevels.Count + count).ToString ();
+                }
+
+                toplevel.Id = (TopLevels.Count + count).ToString ();
+
+                TopLevels.Push (toplevel);
+            }
+            else
+            {
+                Toplevel? dup = TopLevels.FirstOrDefault (x => x.Id == toplevel.Id);
+
+                if (dup is null)
+                {
+                    TopLevels.Push (toplevel);
+                }
+            }
+        }
+
+        if (Top is null)
+        {
+            Top = toplevel;
+        }
+
+        if ((Top?.Modal == false && toplevel.Modal)
+            || (Top?.Modal == false && !toplevel.Modal)
+            || (Top?.Modal == true && toplevel.Modal))
+        {
+            if (toplevel.Visible)
+            {
+                if (Top is { HasFocus: true })
+                {
+                    Top.HasFocus = false;
+                }
+
+                // Force leave events for any entered views in the old Top
+                if (Mouse.GetLastMousePosition () is { })
+                {
+                    Mouse.RaiseMouseEnterLeaveEvents (Mouse.GetLastMousePosition ()!.Value, new ());
+                }
+
+                Top?.OnDeactivate (toplevel);
+                Toplevel previousTop = Top!;
+
+                Top = toplevel;
+                Top.OnActivate (previousTop);
+            }
+        }
+
+        // View implements ISupportInitializeNotification which is derived from ISupportInitialize
+        if (!toplevel.IsInitialized)
+        {
+            toplevel.BeginInit ();
+            toplevel.EndInit (); // Calls Layout
+        }
+
+        // Try to set initial focus to any TabStop
+        if (!toplevel.HasFocus)
+        {
+            toplevel.SetFocus ();
+        }
+
+        toplevel.OnLoaded ();
+
+        Instance.LayoutAndDraw (true);
+
+        if (PositionCursor ())
+        {
+            Driver?.UpdateCursor ();
+        }
+
+        SessionBegun?.Invoke (this, new (rs));
+
+        return rs;
+    }
+
+    /// <inheritdoc/>
+    public bool StopAfterFirstIteration { get; set; }
+
+    /// <inheritdoc/>
+    public event EventHandler<IterationEventArgs>? Iteration;
+
+    /// <inheritdoc/>
+    [RequiresUnreferencedCode ("AOT")]
+    [RequiresDynamicCode ("AOT")]
+    public Toplevel Run (Func<Exception, bool>? errorHandler = null, string? driver = null) { return Run<Toplevel> (errorHandler, driver); }
+
+    /// <inheritdoc/>
+    [RequiresUnreferencedCode ("AOT")]
+    [RequiresDynamicCode ("AOT")]
+    public TView Run<TView> (Func<Exception, bool>? errorHandler = null, string? driver = null)
+        where TView : Toplevel, new ()
+    {
+        if (!Initialized)
+        {
+            // Init() has NOT been called. Auto-initialize as per interface contract.
+            Init (null, driver);
+        }
+
+        TView top = new ();
+        Run (top, errorHandler);
+
+        return top;
+    }
+
+
+    /// <inheritdoc/>
+    public void Run (Toplevel view, Func<Exception, bool>? errorHandler = null)
+    {
+        Logging.Information ($"Run '{view}'");
+        ArgumentNullException.ThrowIfNull (view);
+
+        if (!Initialized)
+        {
+            throw new NotInitializedException (nameof (Run));
+        }
+
+        if (Driver == null)
+        {
+            throw new InvalidOperationException ("Driver was inexplicably null when trying to Run view");
+        }
+
+        Top = view;
+
+        SessionToken rs = Application.Begin (view);
+
+        Top.Running = true;
+
+        var firstIteration = true;
+
+        while (TopLevels.TryPeek (out Toplevel? found) && found == view && view.Running)
+        {
+            if (Coordinator is null)
+            {
+                throw new ($"{nameof (IMainLoopCoordinator)} inexplicably became null during Run");
+            }
+
+            Coordinator.RunIteration ();
+
+            if (StopAfterFirstIteration && firstIteration)
+            {
+                Logging.Information ("Run - Stopping after first iteration as requested");
+                view.RequestStop ();
+            }
+
+            firstIteration = false;
+        }
+
+        Logging.Information ("Run - Calling End");
+        Application.End (rs);
+    }
+
+    /// <inheritdoc/>
+    public void End (SessionToken sessionToken)
+    {
+        ArgumentNullException.ThrowIfNull (sessionToken);
+
+        if (Popover?.GetActivePopover () as View is { Visible: true } visiblePopover)
+        {
+            ApplicationPopover.HideWithQuitCommand (visiblePopover);
+        }
+
+        sessionToken.Toplevel.OnUnloaded ();
+
+        // End the Session
+        // First, take it off the Toplevel Stack
+        if (TopLevels.TryPop (out Toplevel? topOfStack))
+        {
+            if (topOfStack != sessionToken.Toplevel)
+            {
+                // If the top of the stack is not the SessionToken.Toplevel then
+                // this call to End is not balanced with the call to Begin that started the Session
+                throw new ArgumentException ("End must be balanced with calls to Begin");
+            }
+        }
+
+        // Notify that it is closing
+        sessionToken.Toplevel?.OnClosed (sessionToken.Toplevel);
+
+        if (TopLevels.TryPeek (out Toplevel? newTop))
+        {
+            Top = newTop;
+            Top?.SetNeedsDraw ();
+        }
+
+        if (sessionToken.Toplevel is { HasFocus: true })
+        {
+            sessionToken.Toplevel.HasFocus = false;
+        }
+
+        if (Top is { HasFocus: false })
+        {
+            Top.SetFocus ();
+        }
+
+        CachedSessionTokenToplevel = sessionToken.Toplevel;
+
+        sessionToken.Toplevel = null;
+        sessionToken.Dispose ();
+
+        // BUGBUG: Why layout and draw here? This causes the screen to be cleared!
+        //LayoutAndDraw (true);
+
+        SessionEnded?.Invoke (this, new (CachedSessionTokenToplevel));
+    }
+
+    /// <inheritdoc/>
+    public void RequestStop () { RequestStop (null); }
+
+    /// <inheritdoc/>
+    public void RequestStop (Toplevel? top)
+    {
+        Logging.Trace ($"Top: '{(top is { } ? top : "null")}'");
+
+        top ??= Top;
+
+        if (top == null)
+        {
+            return;
+        }
+
+        ToplevelClosingEventArgs ev = new (top);
+        top.OnClosing (ev);
+
+        if (ev.Cancel)
+        {
+            return;
+        }
+
+        top.Running = false;
+    }
+
+    /// <inheritdoc/>
+    public void RaiseIteration () { Iteration?.Invoke (null, new ()); }
+
+    #endregion Begin->Run->Stop->End
+
+    #region Timeouts and Invoke
+
+    private readonly ITimedEvents _timedEvents = new TimedEvents ();
+
+    /// <inheritdoc/>
+    public ITimedEvents? TimedEvents => _timedEvents;
+
+    /// <inheritdoc/>
+    public object AddTimeout (TimeSpan time, Func<bool> callback) { return _timedEvents.Add (time, callback); }
+
+    /// <inheritdoc/>
+    public bool RemoveTimeout (object token) { return _timedEvents.Remove (token); }
+
+    /// <inheritdoc/>
+    public void Invoke (Action action)
+    {
+        // If we are already on the main UI thread
+        if (Top is { Running: true } && MainThreadId == Thread.CurrentThread.ManagedThreadId)
+        {
+            action ();
+
+            return;
+        }
+
+        _timedEvents.Add (
+                          TimeSpan.Zero,
+                          () =>
+                          {
+                              action ();
+
+                              return false;
+                          }
+                         );
+    }
+
+    #endregion Timeouts and Invoke
+}

Terminal.Gui/App/ApplicationImpl.Screen.cs

@@ -0,0 +1,177 @@
+#nullable enable
+
+namespace Terminal.Gui.App;
+
+public partial class ApplicationImpl
+{
+    /// <inheritdoc/>
+    public event EventHandler<EventArgs<Rectangle>>? ScreenChanged;
+
+    private readonly object _lockScreen = new ();
+    private Rectangle? _screen;
+
+    /// <inheritdoc/>
+    public Rectangle Screen
+    {
+        get
+        {
+            lock (_lockScreen)
+            {
+                if (_screen == null)
+                {
+                    _screen = Driver?.Screen ?? new (new (0, 0), new (2048, 2048));
+                }
+
+                return _screen.Value;
+            }
+        }
+        set
+        {
+            if (value is { } && (value.X != 0 || value.Y != 0))
+            {
+                throw new NotImplementedException ("Screen locations other than 0, 0 are not yet supported");
+            }
+
+            lock (_lockScreen)
+            {
+                _screen = value;
+            }
+        }
+    }
+
+    /// <inheritdoc/>
+    public bool ClearScreenNextIteration { get; set; }
+
+    /// <inheritdoc/>
+    public bool PositionCursor ()
+    {
+        // Find the most focused view and position the cursor there.
+        View? mostFocused = Navigation?.GetFocused ();
+
+        // If the view is not visible or enabled, don't position the cursor
+        if (mostFocused is null || !mostFocused.Visible || !mostFocused.Enabled)
+        {
+            var current = CursorVisibility.Invisible;
+            Driver?.GetCursorVisibility (out current);
+
+            if (current != CursorVisibility.Invisible)
+            {
+                Driver?.SetCursorVisibility (CursorVisibility.Invisible);
+            }
+
+            return false;
+        }
+
+        // If the view is not visible within it's superview, don't position the cursor
+        Rectangle mostFocusedViewport = mostFocused.ViewportToScreen (mostFocused.Viewport with { Location = Point.Empty });
+
+        Rectangle superViewViewport =
+            mostFocused.SuperView?.ViewportToScreen (mostFocused.SuperView.Viewport with { Location = Point.Empty }) ?? Driver!.Screen;
+
+        if (!superViewViewport.IntersectsWith (mostFocusedViewport))
+        {
+            return false;
+        }
+
+        Point? cursor = mostFocused.PositionCursor ();
+
+        Driver!.GetCursorVisibility (out CursorVisibility currentCursorVisibility);
+
+        if (cursor is { })
+        {
+            // Convert cursor to screen coords
+            cursor = mostFocused.ViewportToScreen (mostFocused.Viewport with { Location = cursor.Value }).Location;
+
+            // If the cursor is not in a visible location in the SuperView, hide it
+            if (!superViewViewport.Contains (cursor.Value))
+            {
+                if (currentCursorVisibility != CursorVisibility.Invisible)
+                {
+                    Driver.SetCursorVisibility (CursorVisibility.Invisible);
+                }
+
+                return false;
+            }
+
+            // Show it
+            if (currentCursorVisibility == CursorVisibility.Invisible)
+            {
+                Driver.SetCursorVisibility (mostFocused.CursorVisibility);
+            }
+
+            return true;
+        }
+
+        if (currentCursorVisibility != CursorVisibility.Invisible)
+        {
+            Driver.SetCursorVisibility (CursorVisibility.Invisible);
+        }
+
+        return false;
+    }
+
+    /// <summary>
+    ///     INTERNAL: Resets the Screen field to null so it will be recalculated on next access.
+    /// </summary>
+    private void ResetScreen ()
+    {
+        lock (_lockScreen)
+        {
+            _screen = null;
+        }
+    }
+
+    /// <summary>
+    ///     INTERNAL: Called when the application's size has changed. Sets the size of all <see cref="Toplevel"/>s and fires
+    ///     the
+    ///     <see cref="ScreenChanged"/> event.
+    /// </summary>
+    /// <param name="screen">The new screen size and position.</param>
+    private void RaiseScreenChangedEvent (Rectangle screen)
+    {
+        Screen = new (Point.Empty, screen.Size);
+
+        ScreenChanged?.Invoke (this, new (screen));
+
+        foreach (Toplevel t in TopLevels)
+        {
+            t.OnSizeChanging (new (screen.Size));
+            t.SetNeedsLayout ();
+        }
+
+        LayoutAndDraw (true);
+    }
+
+    private void Driver_SizeChanged (object? sender, SizeChangedEventArgs e) { RaiseScreenChangedEvent (new (new (0, 0), e.Size!.Value)); }
+
+    /// <inheritdoc/>
+    public void LayoutAndDraw (bool forceRedraw = false)
+    {
+        List<View> tops = [.. TopLevels];
+
+        if (Popover?.GetActivePopover () as View is { Visible: true } visiblePopover)
+        {
+            visiblePopover.SetNeedsDraw ();
+            visiblePopover.SetNeedsLayout ();
+            tops.Insert (0, visiblePopover);
+        }
+
+        bool neededLayout = View.Layout (tops.ToArray ().Reverse (), Screen.Size);
+
+        if (ClearScreenNextIteration)
+        {
+            forceRedraw = true;
+            ClearScreenNextIteration = false;
+        }
+
+        if (forceRedraw)
+        {
+            Driver?.ClearContents ();
+        }
+
+        View.SetClipToScreen ();
+        View.Draw (tops, neededLayout || forceRedraw);
+        View.SetClipToScreen ();
+        Driver?.Refresh ();
+    }
+}

Terminal.Gui/App/ApplicationImpl.cs

@@ -1,54 +1,55 @@
 #nullable enable
 using System.Collections.Concurrent;
-using System.Diagnostics;
-using System.Diagnostics.CodeAnalysis;
-using Microsoft.Extensions.Logging;
-using Terminal.Gui.Drivers;
 
 namespace Terminal.Gui.App;
 
 /// <summary>
-/// Implementation of core <see cref="Application"/> methods using the modern
-/// main loop architecture with component factories for different platforms.
+///     Implementation of core <see cref="Application"/> methods using the modern
+///     main loop architecture with component factories for different platforms.
 /// </summary>
-public class ApplicationImpl : IApplication
+public partial class ApplicationImpl : IApplication
 {
-    private readonly IComponentFactory? _componentFactory;
-    private IMainLoopCoordinator? _coordinator;
-    private string? _driverName;
-    private readonly ITimedEvents _timedEvents = new TimedEvents ();
-    private IConsoleDriver? _driver;
-    private bool _initialized;
-    private ApplicationPopover? _popover;
-    private ApplicationNavigation? _navigation;
-    private Toplevel? _top;
-    private readonly ConcurrentStack<Toplevel> _topLevels = new ();
-    private int _mainThreadId = -1;
-    private bool _force16Colors;
-    private string _forceDriver = string.Empty;
-    private readonly List<SixelToRender> _sixel = new ();
-    private readonly object _lockScreen = new ();
-    private Rectangle? _screen;
-    private bool _clearScreenNextIteration;
+    /// <summary>
+    ///     Creates a new instance of the Application backend.
+    /// </summary>
+    public ApplicationImpl () { }
+
+    /// <summary>
+    ///     INTERNAL: Creates a new instance of the Application backend.
+    /// </summary>
+    /// <param name="componentFactory"></param>
+    internal ApplicationImpl (IComponentFactory componentFactory) { _componentFactory = componentFactory; }
+
+    #region Singleton
 
     // Private static readonly Lazy instance of Application
     private static Lazy<IApplication> _lazyInstance = new (() => new ApplicationImpl ());
 
     /// <summary>
-    /// Gets the currently configured backend implementation of <see cref="Application"/> gateway methods.
-    /// Change to your own implementation by using <see cref="ChangeInstance"/> (before init).
+    ///     Change the singleton implementation, should not be called except before application
+    ///     startup. This method lets you provide alternative implementations of core static gateway
+    ///     methods of <see cref="Application"/>.
+    /// </summary>
+    /// <param name="newApplication"></param>
+    public static void ChangeInstance (IApplication? newApplication) { _lazyInstance = new (newApplication!); }
+
+    /// <summary>
+    ///     Gets the currently configured backend implementation of <see cref="Application"/> gateway methods.
+    ///     Change to your own implementation by using <see cref="ChangeInstance"/> (before init).
     /// </summary>
     public static IApplication Instance => _lazyInstance.Value;
 
-    /// <inheritdoc/>
-    public ITimedEvents? TimedEvents => _timedEvents;
+    #endregion Singleton
+
+    private string? _driverName;
 
-    internal IMainLoopCoordinator? Coordinator => _coordinator;
+
+    #region Input
 
     private IMouse? _mouse;
 
     /// <summary>
-    /// Handles mouse event state and processing.
+    ///     Handles mouse event state and processing.
     /// </summary>
     public IMouse Mouse
     {
@@ -58,20 +59,17 @@ public class ApplicationImpl : IApplication
             {
                 _mouse = new MouseImpl { Application = this };
             }
+
             return _mouse;
         }
         set => _mouse = value ?? throw new ArgumentNullException (nameof (value));
     }
 
-    /// <summary>
-    /// Handles which <see cref="View"/> (if any) has captured the mouse
-    /// </summary>
-    public IMouseGrabHandler MouseGrabHandler { get; set; } = new MouseGrabHandler ();
-
     private IKeyboard? _keyboard;
+    private bool _stopAfterFirstIteration;
 
     /// <summary>
-    /// Handles keyboard input and key bindings at the Application level
+    ///     Handles keyboard input and key bindings at the Application level
     /// </summary>
     public IKeyboard Keyboard
     {
@@ -81,487 +79,32 @@ public class ApplicationImpl : IApplication
             {
                 _keyboard = new KeyboardImpl { Application = this };
             }
+
             return _keyboard;
         }
         set => _keyboard = value ?? throw new ArgumentNullException (nameof (value));
     }
 
-    /// <inheritdoc/>
-    public IConsoleDriver? Driver
-    {
-        get => _driver;
-        set => _driver = value;
-    }
-
-    /// <inheritdoc/>
-    public bool Initialized
-    {
-        get => _initialized;
-        set => _initialized = value;
-    }
-
-    /// <inheritdoc/>
-    public bool Force16Colors
-    {
-        get => _force16Colors;
-        set => _force16Colors = value;
-    }
+    #endregion Input
 
-    /// <inheritdoc/>
-    public string ForceDriver
-    {
-        get => _forceDriver;
-        set => _forceDriver = value;
-    }
+    #region View Management
 
     /// <inheritdoc/>
-    public List<SixelToRender> Sixel => _sixel;
+    public ApplicationPopover? Popover { get; set; }
 
     /// <inheritdoc/>
-    public Rectangle Screen
-    {
-        get
-        {
-            lock (_lockScreen)
-            {
-                if (_screen == null)
-                {
-                    _screen = Driver?.Screen ?? new (new (0, 0), new (2048, 2048));
-                }
-
-                return _screen.Value;
-            }
-        }
-        set
-        {
-            if (value is {} && (value.X != 0 || value.Y != 0))
-            {
-                throw new NotImplementedException ($"Screen locations other than 0, 0 are not yet supported");
-            }
-
-            lock (_lockScreen)
-            {
-                _screen = value;
-            }
-        }
-    }
+    public ApplicationNavigation? Navigation { get; set; }
 
     /// <inheritdoc/>
-    public bool ClearScreenNextIteration
-    {
-        get => _clearScreenNextIteration;
-        set => _clearScreenNextIteration = value;
-    }
+    public Toplevel? Top { get; set; }
 
-    /// <inheritdoc/>
-    public ApplicationPopover? Popover
-    {
-        get => _popover;
-        set => _popover = value;
-    }
+    // BUGBUG: Technically, this is not the full lst of TopLevels. There be dragons here, e.g. see how Toplevel.Id is used. What
 
     /// <inheritdoc/>
-    public ApplicationNavigation? Navigation
-    {
-        get => _navigation;
-        set => _navigation = value;
-    }
+    public ConcurrentStack<Toplevel> TopLevels { get; } = new ();
 
     /// <inheritdoc/>
-    public Toplevel? Top
-    {
-        get => _top;
-        set => _top = value;
-    }
-
-    /// <inheritdoc/>
-    public ConcurrentStack<Toplevel> TopLevels => _topLevels;
-
-    /// <summary>
-    /// Gets or sets the main thread ID for the application.
-    /// </summary>
-    internal int MainThreadId
-    {
-        get => _mainThreadId;
-        set => _mainThreadId = value;
-    }
-
-    /// <inheritdoc/>
-    public void RequestStop () => RequestStop (null);
-
-    /// <summary>
-    /// Creates a new instance of the Application backend.
-    /// </summary>
-    public ApplicationImpl ()
-    {
-    }
-
-    internal ApplicationImpl (IComponentFactory componentFactory)
-    {
-        _componentFactory = componentFactory;
-    }
-
-    /// <summary>
-    /// Change the singleton implementation, should not be called except before application
-    /// startup. This method lets you provide alternative implementations of core static gateway
-    /// methods of <see cref="Application"/>.
-    /// </summary>
-    /// <param name="newApplication"></param>
-    public static void ChangeInstance (IApplication newApplication)
-    {
-        _lazyInstance = new Lazy<IApplication> (newApplication);
-    }
-
-    /// <inheritdoc/>
-    [RequiresUnreferencedCode ("AOT")]
-    [RequiresDynamicCode ("AOT")]
-    public void Init (IConsoleDriver? driver = null, string? driverName = null)
-    {
-        if (_initialized)
-        {
-            Logging.Logger.LogError ("Init called multiple times without shutdown, aborting.");
-
-            throw new InvalidOperationException ("Init called multiple times without Shutdown");
-        }
-
-        if (!string.IsNullOrWhiteSpace (driverName))
-        {
-            _driverName = driverName;
-        }
-
-        if (string.IsNullOrWhiteSpace (_driverName))
-        {
-            _driverName = Application.ForceDriver;
-        }
-
-        Debug.Assert(_navigation is null);
-        _navigation = new ();
-
-        Debug.Assert (_popover is null);
-        _popover = new ();
-
-        // Preserve existing keyboard settings if they exist
-        bool hasExistingKeyboard = _keyboard is not null;
-        Key existingQuitKey = _keyboard?.QuitKey ?? Key.Esc;
-        Key existingArrangeKey = _keyboard?.ArrangeKey ?? Key.F5.WithCtrl;
-        Key existingNextTabKey = _keyboard?.NextTabKey ?? Key.Tab;
-        Key existingPrevTabKey = _keyboard?.PrevTabKey ?? Key.Tab.WithShift;
-        Key existingNextTabGroupKey = _keyboard?.NextTabGroupKey ?? Key.F6;
-        Key existingPrevTabGroupKey = _keyboard?.PrevTabGroupKey ?? Key.F6.WithShift;
-
-        // Reset keyboard to ensure fresh state with default bindings
-        _keyboard = new KeyboardImpl { Application = this };
-
-        // Restore previously set keys if they existed and were different from defaults
-        if (hasExistingKeyboard)
-        {
-            _keyboard.QuitKey = existingQuitKey;
-            _keyboard.ArrangeKey = existingArrangeKey;
-            _keyboard.NextTabKey = existingNextTabKey;
-            _keyboard.PrevTabKey = existingPrevTabKey;
-            _keyboard.NextTabGroupKey = existingNextTabGroupKey;
-            _keyboard.PrevTabGroupKey = existingPrevTabGroupKey;
-        }
-
-        CreateDriver (driverName ?? _driverName);
-
-        _initialized = true;
-
-        Application.OnInitializedChanged (this, new (true));
-        Application.SubscribeDriverEvents ();
-
-        SynchronizationContext.SetSynchronizationContext (new ());
-        _mainThreadId = Thread.CurrentThread.ManagedThreadId;
-    }
-
-    private void CreateDriver (string? driverName)
-    {
-        // When running unit tests, always use FakeDriver unless explicitly specified
-        if (ConsoleDriver.RunningUnitTests && 
-            string.IsNullOrEmpty (driverName) && 
-            _componentFactory is null)
-        {
-            Logging.Logger.LogDebug ("Unit test safeguard: forcing FakeDriver (RunningUnitTests=true, driverName=null, componentFactory=null)");
-            _coordinator = CreateSubcomponents (() => new FakeComponentFactory ());
-            _coordinator.StartAsync ().Wait ();
-
-            if (_driver == null)
-            {
-                throw new ("Driver was null even after booting MainLoopCoordinator");
-            }
+    public Toplevel? CachedSessionTokenToplevel { get; set; }
 
-            return;
-        }
-
-        PlatformID p = Environment.OSVersion.Platform;
-
-        // Check component factory type first - this takes precedence over driverName
-        bool factoryIsWindows = _componentFactory is IComponentFactory<WindowsConsole.InputRecord>;
-        bool factoryIsDotNet = _componentFactory is IComponentFactory<ConsoleKeyInfo>;
-        bool factoryIsUnix = _componentFactory is IComponentFactory<char>;
-        bool factoryIsFake = _componentFactory is IComponentFactory<ConsoleKeyInfo>;
-
-        // Then check driverName
-        bool nameIsWindows = driverName?.Contains ("win", StringComparison.OrdinalIgnoreCase) ?? false;
-        bool nameIsDotNet = (driverName?.Contains ("dotnet", StringComparison.OrdinalIgnoreCase) ?? false);
-        bool nameIsUnix = driverName?.Contains ("unix", StringComparison.OrdinalIgnoreCase) ?? false;
-        bool nameIsFake = driverName?.Contains ("fake", StringComparison.OrdinalIgnoreCase) ?? false;
-
-        // Decide which driver to use - component factory type takes priority
-        if (factoryIsFake || (!factoryIsWindows && !factoryIsDotNet && !factoryIsUnix && nameIsFake))
-        {
-            _coordinator = CreateSubcomponents (() => new FakeComponentFactory ());
-        }
-        else if (factoryIsWindows || (!factoryIsDotNet && !factoryIsUnix && nameIsWindows))
-        {
-            _coordinator = CreateSubcomponents (() => new WindowsComponentFactory ());
-        }
-        else if (factoryIsDotNet || (!factoryIsWindows && !factoryIsUnix && nameIsDotNet))
-        {
-            _coordinator = CreateSubcomponents (() => new NetComponentFactory ());
-        }
-        else if (factoryIsUnix || (!factoryIsWindows && !factoryIsDotNet && nameIsUnix))
-        {
-            _coordinator = CreateSubcomponents (() => new UnixComponentFactory ());
-        }
-        else if (p == PlatformID.Win32NT || p == PlatformID.Win32S || p == PlatformID.Win32Windows)
-        {
-            _coordinator = CreateSubcomponents (() => new WindowsComponentFactory ());
-        }
-        else
-        {
-            _coordinator = CreateSubcomponents (() => new UnixComponentFactory ());
-        }
-
-        _coordinator.StartAsync ().Wait ();
-
-        if (_driver == null)
-        {
-            throw new ("Driver was null even after booting MainLoopCoordinator");
-        }
-    }
-
-    private IMainLoopCoordinator CreateSubcomponents<T> (Func<IComponentFactory<T>> fallbackFactory)
-    {
-        ConcurrentQueue<T> inputBuffer = new ();
-        ApplicationMainLoop<T> loop = new ();
-
-        IComponentFactory<T> cf;
-
-        if (_componentFactory is IComponentFactory<T> typedFactory)
-        {
-            cf = typedFactory;
-        }
-        else
-        {
-            cf = fallbackFactory ();
-        }
-
-        return new MainLoopCoordinator<T> (_timedEvents, inputBuffer, loop, cf);
-    }
-
-    /// <summary>
-    ///     Runs the application by creating a <see cref="Toplevel"/> object and calling
-    ///     <see cref="Run(Toplevel, Func{Exception, bool})"/>.
-    /// </summary>
-    /// <returns>The created <see cref="Toplevel"/> object. The caller is responsible for disposing this object.</returns>
-    [RequiresUnreferencedCode ("AOT")]
-    [RequiresDynamicCode ("AOT")]
-    public Toplevel Run (Func<Exception, bool>? errorHandler = null, IConsoleDriver? driver = null) { return Run<Toplevel> (errorHandler, driver); }
-
-    /// <summary>
-    ///     Runs the application by creating a <see cref="Toplevel"/>-derived object of type <c>T</c> and calling
-    ///     <see cref="Run(Toplevel, Func{Exception, bool})"/>.
-    /// </summary>
-    /// <param name="errorHandler"></param>
-    /// <param name="driver">
-    ///     The <see cref="IConsoleDriver"/> to use. If not specified the default driver for the platform will
-    ///     be used. Must be <see langword="null"/> if <see cref="Init"/> has already been called.
-    /// </param>
-    /// <returns>The created T object. The caller is responsible for disposing this object.</returns>
-    [RequiresUnreferencedCode ("AOT")]
-    [RequiresDynamicCode ("AOT")]
-    public T Run<T> (Func<Exception, bool>? errorHandler = null, IConsoleDriver? driver = null)
-        where T : Toplevel, new()
-    {
-        if (!_initialized)
-        {
-            // Init() has NOT been called. Auto-initialize as per interface contract.
-            Init (driver, null);
-        }
-
-        T top = new ();
-        Run (top, errorHandler);
-        return top;
-    }
-
-    /// <summary>Runs the Application using the provided <see cref="Toplevel"/> view.</summary>
-    /// <param name="view">The <see cref="Toplevel"/> to run as a modal.</param>
-    /// <param name="errorHandler">Handler for any unhandled exceptions.</param>
-    public void Run (Toplevel view, Func<Exception, bool>? errorHandler = null)
-    {
-        Logging.Information ($"Run '{view}'");
-        ArgumentNullException.ThrowIfNull (view);
-
-        if (!_initialized)
-        {
-            throw new NotInitializedException (nameof (Run));
-        }
-
-        if (_driver == null)
-        {
-            throw new  InvalidOperationException ("Driver was inexplicably null when trying to Run view");
-        }
-
-        _top = view;
-
-        RunState rs = Application.Begin (view);
-
-        _top.Running = true;
-
-        while (_topLevels.TryPeek (out Toplevel? found) && found == view && view.Running)
-        {
-            if (_coordinator is null)
-            {
-                throw new ($"{nameof (IMainLoopCoordinator)} inexplicably became null during Run");
-            }
-
-            _coordinator.RunIteration ();
-        }
-
-        Logging.Information ($"Run - Calling End");
-        Application.End (rs);
-    }
-
-    /// <summary>Shutdown an application initialized with <see cref="Init"/>.</summary>
-    public void Shutdown ()
-    {
-        _coordinator?.Stop ();
-        
-        bool wasInitialized = _initialized;
-        
-        // Reset Screen before calling Application.ResetState to avoid circular reference
-        ResetScreen ();
-        
-        // Call ResetState FIRST so it can properly dispose Popover and other resources
-        // that are accessed via Application.* static properties that now delegate to instance fields
-        Application.ResetState ();
-        ConfigurationManager.PrintJsonErrors ();
-        
-        // Clear instance fields after ResetState has disposed everything
-        _driver = null;
-        _mouse = null;
-        _keyboard = null;
-        _initialized = false;
-        _navigation = null;
-        _popover = null;
-        _top = null;
-        _topLevels.Clear ();
-        _mainThreadId = -1;
-        _screen = null;
-        _clearScreenNextIteration = false;
-        _sixel.Clear ();
-        // Don't reset ForceDriver and Force16Colors; they need to be set before Init is called
-
-        if (wasInitialized)
-        {
-            bool init = _initialized; // Will be false after clearing fields above
-            Application.OnInitializedChanged (this, new (in init));
-        }
-
-        _lazyInstance = new (() => new ApplicationImpl ());
-    }
-
-    /// <inheritdoc />
-    public void RequestStop (Toplevel? top)
-    {
-        Logging.Logger.LogInformation ($"RequestStop '{(top is {} ? top : "null")}'");
-
-        top ??= _top;
-
-        if (top == null)
-        {
-            return;
-        }
-
-        ToplevelClosingEventArgs ev = new (top);
-        top.OnClosing (ev);
-
-        if (ev.Cancel)
-        {
-            return;
-        }
-
-        top.Running = false;
-    }
-
-    /// <inheritdoc />
-    public void Invoke (Action action)
-    {
-        // If we are already on the main UI thread
-        if (Application.Top is { Running: true } && _mainThreadId == Thread.CurrentThread.ManagedThreadId)
-        {
-            action ();
-            return;
-        }
-
-        _timedEvents.Add (TimeSpan.Zero,
-                              () =>
-                              {
-                                  action ();
-                                  return false;
-                              }
-                             );
-    }
-
-    /// <inheritdoc />
-    public bool IsLegacy => false;
-
-    /// <inheritdoc />
-    public object AddTimeout (TimeSpan time, Func<bool> callback) { return _timedEvents.Add (time, callback); }
-
-    /// <inheritdoc />
-    public bool RemoveTimeout (object token) { return _timedEvents.Remove (token); }
-
-    /// <inheritdoc />
-    public void LayoutAndDraw (bool forceRedraw = false)
-    {
-        List<View> tops = [.. _topLevels];
-
-        if (_popover?.GetActivePopover () as View is { Visible: true } visiblePopover)
-        {
-            visiblePopover.SetNeedsDraw ();
-            visiblePopover.SetNeedsLayout ();
-            tops.Insert (0, visiblePopover);
-        }
-
-        bool neededLayout = View.Layout (tops.ToArray ().Reverse (), Screen.Size);
-
-        if (ClearScreenNextIteration)
-        {
-            forceRedraw = true;
-            ClearScreenNextIteration = false;
-        }
-
-        if (forceRedraw)
-        {
-            _driver?.ClearContents ();
-        }
-
-        View.SetClipToScreen ();
-        View.Draw (tops, neededLayout || forceRedraw);
-        View.SetClipToScreen ();
-        _driver?.Refresh ();
-    }
-
-    /// <summary>
-    /// Resets the Screen field to null so it will be recalculated on next access.
-    /// </summary>
-    internal void ResetScreen ()
-    {
-        lock (_lockScreen)
-        {
-            _screen = null;
-        }
-    }
+    #endregion View Management
 }

Terminal.Gui/App/CWP/CWPPropertyHelper.cs

@@ -22,7 +22,10 @@ public static class CWPPropertyHelper
     ///     The type of the property value, which may be a nullable reference type (e.g., <see cref="string"/>
     ///     ?).
     /// </typeparam>
-    /// <param name="currentValue">The current property value, which may be null for nullable types.</param>
+    /// <param name="currentValue">
+    ///     Reference to the current property value, which may be null for nullable types. If the change is not cancelled, this
+    ///     will be set to <paramref name="finalValue"/>.
+    /// </param>
     /// <param name="newValue">The proposed new property value, which may be null for nullable types.</param>
     /// <param name="onChanging">The virtual method invoked before the change, returning true to cancel.</param>
     /// <param name="changingEvent">The pre-change event raised to allow modification or cancellation.</param>
@@ -52,9 +55,9 @@ public static class CWPPropertyHelper
     ///     </code>
     /// </example>
     public static bool ChangeProperty<T> (
-        T currentValue,
+        ref T currentValue,
         T newValue,
-        Func<ValueChangingEventArgs<T>, bool> onChanging,
+        Func<ValueChangingEventArgs<T>, bool>? onChanging,
         EventHandler<ValueChangingEventArgs<T>>? changingEvent,
         Action<T> doWork,
         Action<ValueChangedEventArgs<T>>? onChanged,
@@ -70,13 +73,17 @@ public static class CWPPropertyHelper
         }
 
         ValueChangingEventArgs<T> args = new (currentValue, newValue);
-        bool cancelled = onChanging (args) || args.Handled;
 
-        if (cancelled)
+        if (onChanging is { })
         {
-            finalValue = currentValue;
+            bool cancelled = onChanging (args) || args.Handled;
 
-            return false;
+            if (cancelled)
+            {
+                finalValue = currentValue;
+
+                return false;
+            }
         }
 
         changingEvent?.Invoke (null, args);
@@ -100,6 +107,7 @@ public static class CWPPropertyHelper
         doWork (finalValue);
         
         ValueChangedEventArgs<T> changedArgs = new (currentValue, finalValue);
+        currentValue = finalValue;
         onChanged?.Invoke (changedArgs);
         changedEvent?.Invoke (null, changedArgs);
 

Terminal.Gui/App/Clipboard/ClipboardBase.cs

@@ -103,7 +103,7 @@ public abstract class ClipboardBase : IClipboard
     }
 
     /// <summary>
-    ///     Returns the contents of the OS clipboard if possible. Implemented by <see cref="IConsoleDriver"/>-specific
+    ///     Returns the contents of the OS clipboard if possible. Implemented by <see cref="IDriver"/>-specific
     ///     subclasses.
     /// </summary>
     /// <returns>The contents of the OS clipboard if successful.</returns>
@@ -111,7 +111,7 @@ public abstract class ClipboardBase : IClipboard
     protected abstract string GetClipboardDataImpl ();
 
     /// <summary>
-    ///     Pastes the <paramref name="text"/> to the OS clipboard if possible. Implemented by <see cref="IConsoleDriver"/>
+    ///     Pastes the <paramref name="text"/> to the OS clipboard if possible. Implemented by <see cref="IDriver"/>
     ///     -specific subclasses.
     /// </summary>
     /// <param name="text">The text to paste to the OS clipboard.</param>

Terminal.Gui/App/Clipboard/ClipboardProcessRunner.cs

@@ -5,7 +5,7 @@ namespace Terminal.Gui.App;
 
 /// <summary>
 ///     Helper class for console drivers to invoke shell commands to interact with the clipboard. Used primarily by
-///     UnixDriver, but also used in Unit tests which is why it is in IConsoleDriver.cs.
+///     UnixDriver, but also used in Unit tests which is why it is in IDriver.cs.
 /// </summary>
 internal static class ClipboardProcessRunner
 {

Terminal.Gui/App/IApplication.cs

@@ -1,4 +1,5 @@
 #nullable enable
+using System.Collections.Concurrent;
 using System.Diagnostics.CodeAnalysis;
 
 namespace Terminal.Gui.App;
@@ -9,252 +10,533 @@ namespace Terminal.Gui.App;
 /// </summary>
 public interface IApplication
 {
-    /// <summary>Adds a timeout to the application.</summary>
-    /// <remarks>
-    ///     When time specified passes, the callback will be invoked. If the callback returns true, the timeout will be
-    ///     reset, repeating the invocation. If it returns false, the timeout will stop and be removed. The returned value is a
-    ///     token that can be used to stop the timeout by calling <see cref="RemoveTimeout(object)"/>.
-    /// </remarks>
-    object AddTimeout (TimeSpan time, Func<bool> callback);
+    #region Keyboard
 
     /// <summary>
-    /// Handles keyboard input and key bindings at the Application level.
+    ///     Handles keyboard input and key bindings at the Application level.
     /// </summary>
+    /// <remarks>
+    ///     <para>
+    ///         Provides access to keyboard state, key bindings, and keyboard event handling. Set during <see cref="Init"/>.
+    ///     </para>
+    /// </remarks>
     IKeyboard Keyboard { get; set; }
 
+    #endregion Keyboard
+
+    #region Mouse
+
     /// <summary>
     ///     Handles mouse event state and processing.
     /// </summary>
+    /// <remarks>
+    ///     <para>
+    ///         Provides access to mouse state, mouse grabbing, and mouse event handling. Set during <see cref="Init"/>.
+    ///     </para>
+    /// </remarks>
     IMouse Mouse { get; set; }
 
-    /// <summary>Gets or sets the console driver being used.</summary>
-    IConsoleDriver? Driver { get; set; }
+    #endregion Mouse
+
+    #region Initialization and Shutdown
+
+    /// <summary>Initializes a new instance of <see cref="Terminal.Gui"/> Application.</summary>
+    /// <param name="driver">
+    ///     The <see cref="IDriver"/> to use. If neither <paramref name="driver"/> or
+    ///     <paramref name="driverName"/> are specified the default driver for the platform will be used.
+    /// </param>
+    /// <param name="driverName">
+    ///     The short name (e.g. "dotnet", "windows", "unix", or "fake") of the
+    ///     <see cref="IDriver"/> to use. If neither <paramref name="driver"/> or <paramref name="driverName"/> are
+    ///     specified the default driver for the platform will be used.
+    /// </param>
+    /// <remarks>
+    ///     <para>Call this method once per instance (or after <see cref="Shutdown"/> has been called).</para>
+    ///     <para>
+    ///         This function loads the right <see cref="IDriver"/> for the platform, creates a main loop coordinator,
+    ///         initializes keyboard and mouse handlers, and subscribes to driver events.
+    ///     </para>
+    ///     <para>
+    ///         <see cref="Shutdown"/> must be called when the application is closing (typically after
+    ///         <see cref="Run{T}"/> has returned) to ensure resources are cleaned up and terminal settings restored.
+    ///     </para>
+    ///     <para>
+    ///         The <see cref="Run{T}"/> function combines <see cref="Init(IDriver,string)"/> and
+    ///         <see cref="Run(Toplevel, Func{Exception, bool})"/> into a single call. An application can use
+    ///         <see cref="Run{T}"/> without explicitly calling <see cref="Init(IDriver,string)"/>.
+    ///     </para>
+    /// </remarks>
+    [RequiresUnreferencedCode ("AOT")]
+    [RequiresDynamicCode ("AOT")]
+    public void Init (IDriver? driver = null, string? driverName = null);
+
+    /// <summary>
+    ///     This event is raised after the <see cref="Init"/> and <see cref="Shutdown"/> methods have been called.
+    /// </summary>
+    /// <remarks>
+    ///     Intended to support unit tests that need to know when the application has been initialized.
+    /// </remarks>
+    public event EventHandler<EventArgs<bool>>? InitializedChanged;
 
     /// <summary>Gets or sets whether the application has been initialized.</summary>
     bool Initialized { get; set; }
 
+    /// <summary>Shutdown an application initialized with <see cref="Init"/>.</summary>
+    /// <remarks>
+    ///     Shutdown must be called for every call to <see cref="Init"/> or
+    ///     <see cref="Application.Run(Toplevel, Func{Exception, bool})"/> to ensure all resources are cleaned
+    ///     up (Disposed) and terminal settings are restored.
+    /// </remarks>
+    public void Shutdown ();
+
     /// <summary>
-    ///     Gets or sets whether <see cref="Driver"/> will be forced to output only the 16 colors defined in
-    ///     <see cref="ColorName16"/>. The default is <see langword="false"/>, meaning 24-bit (TrueColor) colors will be output
-    ///     as long as the selected <see cref="IConsoleDriver"/> supports TrueColor.
+    ///     Resets the state of this instance.
     /// </summary>
-    bool Force16Colors { get; set; }
+    /// <param name="ignoreDisposed">If true, ignores disposed state checks during reset.</param>
+    /// <remarks>
+    ///     <para>
+    ///         Encapsulates all setting of initial state for Application; having this in a function like this ensures we
+    ///         don't make mistakes in guaranteeing that the state of this singleton is deterministic when <see cref="Init"/>
+    ///         starts running and after <see cref="Shutdown"/> returns.
+    ///     </para>
+    ///     <para>
+    ///         IMPORTANT: Ensure all property/fields are reset here. See Init_ResetState_Resets_Properties unit test.
+    ///     </para>
+    /// </remarks>
+    public void ResetState (bool ignoreDisposed = false);
+
+    #endregion Initialization and Shutdown
+
+    #region Begin->Run->Iteration->Stop->End
 
     /// <summary>
-    ///     Forces the use of the specified driver (one of "fake", "dotnet", "windows", or "unix"). If not
-    ///     specified, the driver is selected based on the platform.
+    ///     Building block API: Creates a <see cref="SessionToken"/> and prepares the provided <see cref="Toplevel"/> for
+    ///     execution. Not usually called directly by applications. Use <see cref="Run(Toplevel, Func{Exception, bool})"/>
+    ///     instead.
     /// </summary>
-    string ForceDriver { get; set; }
+    /// <returns>
+    ///     The <see cref="SessionToken"/> that needs to be passed to the <see cref="End(SessionToken)"/> method upon
+    ///     completion.
+    /// </returns>
+    /// <param name="toplevel">The <see cref="Toplevel"/> to prepare execution for.</param>
+    /// <remarks>
+    ///     <para>
+    ///         This method prepares the provided <see cref="Toplevel"/> for running. It adds this to the
+    ///         list of <see cref="Toplevel"/>s, lays out the SubViews, focuses the first element, and draws the
+    ///         <see cref="Toplevel"/> on the screen. This is usually followed by starting the main loop, and then the
+    ///         <see cref="End(SessionToken)"/> method upon termination which will undo these changes.
+    ///     </para>
+    ///     <para>
+    ///         Raises the <see cref="SessionBegun"/> event before returning.
+    ///     </para>
+    /// </remarks>
+    public SessionToken Begin (Toplevel toplevel);
 
     /// <summary>
-    /// Collection of sixel images to write out to screen when updating.
-    /// Only add to this collection if you are sure terminal supports sixel format.
+    ///     Runs a new Session creating a <see cref="Toplevel"/> and calling <see cref="Begin(Toplevel)"/>. When the session is
+    ///     stopped, <see cref="End(SessionToken)"/> will be called.
     /// </summary>
-    List<SixelToRender> Sixel { get; }
+    /// <param name="errorHandler">Handler for any unhandled exceptions (resumes when returns true, rethrows when null).</param>
+    /// <param name="driver">
+    ///     The driver name. If not specified the default driver for the platform will be used. Must be
+    ///     <see langword="null"/> if <see cref="Init"/> has already been called.
+    /// </param>
+    /// <returns>The created <see cref="Toplevel"/>. The caller is responsible for disposing this object.</returns>
+    /// <remarks>
+    ///     <para>Calling <see cref="Init"/> first is not needed as this function will initialize the application.</para>
+    ///     <para>
+    ///         <see cref="Shutdown"/> must be called when the application is closing (typically after Run has returned) to
+    ///         ensure resources are cleaned up and terminal settings restored.
+    ///     </para>
+    ///     <para>
+    ///         The caller is responsible for disposing the object returned by this method.
+    ///     </para>
+    /// </remarks>
+    [RequiresUnreferencedCode ("AOT")]
+    [RequiresDynamicCode ("AOT")]
+    public Toplevel Run (Func<Exception, bool>? errorHandler = null, string? driver = null);
 
     /// <summary>
-    ///     Gets or sets the size of the screen. By default, this is the size of the screen as reported by the <see cref="IConsoleDriver"/>.
+    ///     Runs a new Session creating a <see cref="Toplevel"/>-derived object of type <typeparamref name="TView"/>
+    ///     and calling <see cref="Run(Toplevel, Func{Exception, bool})"/>. When the session is stopped,
+    ///     <see cref="End(SessionToken)"/> will be called.
     /// </summary>
-    Rectangle Screen { get; set; }
+    /// <typeparam name="TView">The type of <see cref="Toplevel"/> to create and run.</typeparam>
+    /// <param name="errorHandler">Handler for any unhandled exceptions (resumes when returns true, rethrows when null).</param>
+    /// <param name="driver">
+    ///     The driver name. If not specified the default driver for the platform will be used. Must be
+    ///     <see langword="null"/> if <see cref="Init"/> has already been called.
+    /// </param>
+    /// <returns>The created <typeparamref name="TView"/> object. The caller is responsible for disposing this object.</returns>
+    /// <remarks>
+    ///     <para>
+    ///         This method is used to start processing events for the main application, but it is also used to run other
+    ///         modal <see cref="View"/>s such as <see cref="Dialog"/> boxes.
+    ///     </para>
+    ///     <para>
+    ///         To make <see cref="Run(Toplevel, Func{Exception, bool})"/> stop execution, call
+    ///         <see cref="RequestStop()"/> or <see cref="RequestStop(Toplevel)"/>.
+    ///     </para>
+    ///     <para>
+    ///         Calling <see cref="Run(Toplevel, Func{Exception, bool})"/> is equivalent to calling
+    ///         <see cref="Begin(Toplevel)"/>, followed by starting the main loop, and then calling
+    ///         <see cref="End(SessionToken)"/>.
+    ///     </para>
+    ///     <para>
+    ///         When using <see cref="Run{T}"/> or <see cref="Run(Func{Exception, bool}, string)"/>,
+    ///         <see cref="Init"/> will be called automatically.
+    ///     </para>
+    ///     <para>
+    ///         In RELEASE builds: When <paramref name="errorHandler"/> is <see langword="null"/> any exceptions will be
+    ///         rethrown. Otherwise, <paramref name="errorHandler"/> will be called. If <paramref name="errorHandler"/>
+    ///         returns <see langword="true"/> the main loop will resume; otherwise this method will exit.
+    ///     </para>
+    ///     <para>
+    ///         <see cref="Shutdown"/> must be called when the application is closing (typically after Run has returned) to
+    ///         ensure resources are cleaned up and terminal settings restored.
+    ///     </para>
+    ///     <para>
+    ///         In RELEASE builds: When <paramref name="errorHandler"/> is <see langword="null"/> any exceptions will be
+    ///         rethrown. Otherwise, <paramref name="errorHandler"/> will be called. If <paramref name="errorHandler"/>
+    ///         returns <see langword="true"/> the main loop will resume; otherwise this method will exit.
+    ///     </para>
+    ///     <para>
+    ///         The caller is responsible for disposing the object returned by this method.
+    ///     </para>
+    /// </remarks>
+    [RequiresUnreferencedCode ("AOT")]
+    [RequiresDynamicCode ("AOT")]
+    public TView Run<TView> (Func<Exception, bool>? errorHandler = null, string? driver = null)
+        where TView : Toplevel, new ();
 
     /// <summary>
-    ///     Gets or sets whether the screen will be cleared, and all Views redrawn, during the next Application iteration.
+    ///     Runs a new Session using the provided <see cref="Toplevel"/> view and calling
+    ///     <see cref="Run(Toplevel, Func{Exception, bool})"/>.
+    ///     When the session is stopped, <see cref="End(SessionToken)"/> will be called..
     /// </summary>
-    bool ClearScreenNextIteration { get; set; }
+    /// <param name="view">The <see cref="Toplevel"/> to run as a modal.</param>
+    /// <param name="errorHandler">Handler for any unhandled exceptions (resumes when returns true, rethrows when null).</param>
+    /// <remarks>
+    ///     <para>
+    ///         This method is used to start processing events for the main application, but it is also used to run other
+    ///         modal <see cref="View"/>s such as <see cref="Dialog"/> boxes.
+    ///     </para>
+    ///     <para>
+    ///         To make <see cref="Run(Toplevel, Func{Exception, bool})"/> stop execution, call
+    ///         <see cref="RequestStop()"/> or <see cref="RequestStop(Toplevel)"/>.
+    ///     </para>
+    ///     <para>
+    ///         Calling <see cref="Run(Toplevel, Func{Exception, bool})"/> is equivalent to calling
+    ///         <see cref="Begin(Toplevel)"/>, followed by starting the main loop, and then calling
+    ///         <see cref="End(SessionToken)"/>.
+    ///     </para>
+    ///     <para>
+    ///         When using <see cref="Run{T}"/> or <see cref="Run(Func{Exception, bool}, string)"/>,
+    ///         <see cref="Init"/> will be called automatically.
+    ///     </para>
+    ///     <para>
+    ///         <see cref="Shutdown"/> must be called when the application is closing (typically after Run has returned) to
+    ///         ensure resources are cleaned up and terminal settings restored.
+    ///     </para>
+    ///     <para>
+    ///         In RELEASE builds: When <paramref name="errorHandler"/> is <see langword="null"/> any exceptions will be
+    ///         rethrown. Otherwise, <paramref name="errorHandler"/> will be called. If <paramref name="errorHandler"/>
+    ///         returns <see langword="true"/> the main loop will resume; otherwise this method will exit.
+    ///     </para>
+    ///     <para>
+    ///         The caller is responsible for disposing the object returned by this method.
+    ///     </para>
+    /// </remarks>
+    public void Run (Toplevel view, Func<Exception, bool>? errorHandler = null);
 
-    /// <summary>Gets or sets the popover manager.</summary>
-    ApplicationPopover? Popover { get; set; }
+    /// <summary>
+    ///     Raises the <see cref="Iteration"/> event.
+    /// </summary>
+    /// <remarks>
+    ///     This is called once per main loop iteration, before processing input, timeouts, or rendering.
+    /// </remarks>
+    public void RaiseIteration ();
 
-    /// <summary>Gets or sets the navigation manager.</summary>
-    ApplicationNavigation? Navigation { get; set; }
+    /// <summary>This event is raised on each iteration of the main loop.</summary>
+    /// <remarks>
+    ///     <para>
+    ///         This event is raised before input processing, timeout callbacks, and rendering occur each iteration.
+    ///     </para>
+    ///     <para>See also <see cref="AddTimeout"/> and <see cref="TimedEvents"/>.</para>
+    /// </remarks>
+    public event EventHandler<IterationEventArgs>? Iteration;
 
-    /// <summary>Gets the currently active Toplevel.</summary>
-    Toplevel? Top { get; set; }
+    /// <summary>Runs <paramref name="action"/> on the main UI loop thread.</summary>
+    /// <param name="action">The action to be invoked on the main processing thread.</param>
+    /// <remarks>
+    ///     <para>
+    ///         If called from the main thread, the action is executed immediately. Otherwise, it is queued via
+    ///         <see cref="AddTimeout"/> with <see cref="TimeSpan.Zero"/> and will be executed on the next main loop
+    ///         iteration.
+    ///     </para>
+    /// </remarks>
+    void Invoke (Action action);
 
-    /// <summary>Gets the stack of all Toplevels.</summary>
-    System.Collections.Concurrent.ConcurrentStack<Toplevel> TopLevels { get; }
+    /// <summary>
+    ///     Building block API: Ends a Session and completes the execution of a <see cref="Toplevel"/> that was started with
+    ///     <see cref="Begin(Toplevel)"/>. Not usually called directly by applications.
+    ///     <see cref="Run(Toplevel, Func{Exception, bool})"/>
+    ///     will automatically call this method when the session is stopped.
+    /// </summary>
+    /// <param name="sessionToken">The <see cref="SessionToken"/> returned by the <see cref="Begin(Toplevel)"/> method.</param>
+    /// <remarks>
+    ///     <para>
+    ///         This method removes the <see cref="Toplevel"/> from the stack, raises the <see cref="SessionEnded"/>
+    ///         event, and disposes the <paramref name="sessionToken"/>.
+    ///     </para>
+    /// </remarks>
+    public void End (SessionToken sessionToken);
 
-    /// <summary>Requests that the application stop running.</summary>
+    /// <summary>Requests that the currently running Session stop. The Session will stop after the current iteration completes.</summary>
+    /// <remarks>
+    ///     <para>This will cause <see cref="Run(Toplevel, Func{Exception, bool})"/> to return.</para>
+    ///     <para>
+    ///         This is equivalent to calling <see cref="RequestStop(Toplevel)"/> with <see cref="Top"/> as the parameter.
+    ///     </para>
+    /// </remarks>
     void RequestStop ();
 
+    /// <summary>Requests that the currently running Session stop. The Session will stop after the current iteration completes.</summary>
+    /// <param name="top">
+    ///     The <see cref="Toplevel"/> to stop. If <see langword="null"/>, stops the currently running <see cref="Top"/>.
+    /// </param>
+    /// <remarks>
+    ///     <para>This will cause <see cref="Run(Toplevel, Func{Exception, bool})"/> to return.</para>
+    ///     <para>
+    ///         Calling <see cref="RequestStop(Toplevel)"/> is equivalent to setting the <see cref="Toplevel.Running"/>
+    ///         property on the specified <see cref="Toplevel"/> to <see langword="false"/>.
+    ///     </para>
+    /// </remarks>
+    void RequestStop (Toplevel? top);
+
     /// <summary>
-    ///     Causes any Toplevels that need layout to be laid out. Then draws any Toplevels that need display. Only Views that
-    ///     need to be laid out (see <see cref="View.NeedsLayout"/>) will be laid out.
-    ///     Only Views that need to be drawn (see <see cref="View.NeedsDraw"/>) will be drawn.
+    ///     Set to <see langword="true"/> to cause the session to stop running after first iteration.
     /// </summary>
-    /// <param name="forceRedraw">
-    ///     If <see langword="true"/> the entire View hierarchy will be redrawn. The default is <see langword="false"/> and
-    ///     should only be overriden for testing.
-    /// </param>
-    public void LayoutAndDraw (bool forceRedraw = false);
+    /// <remarks>
+    ///     <para>
+    ///         Used primarily for unit testing. When <see langword="true"/>, <see cref="End"/> will be called
+    ///         automatically after the first main loop iteration.
+    ///     </para>
+    /// </remarks>
+    bool StopAfterFirstIteration { get; set; }
 
-    /// <summary>Initializes a new instance of <see cref="Terminal.Gui"/> Application.</summary>
-    /// <para>Call this method once per instance (or after <see cref="Shutdown"/> has been called).</para>
-    /// <para>
-    ///     This function loads the right <see cref="IConsoleDriver"/> for the platform, Creates a <see cref="Toplevel"/>. and
-    ///     assigns it to <see cref="Application.Top"/>
-    /// </para>
-    /// <para>
-    ///     <see cref="Shutdown"/> must be called when the application is closing (typically after
-    ///     <see cref="Run{T}"/> has returned) to ensure resources are cleaned up and
-    ///     terminal settings
-    ///     restored.
-    /// </para>
-    /// <para>
-    ///     The <see cref="Run{T}"/> function combines
-    ///     <see cref="Init(IConsoleDriver,string)"/> and <see cref="Run(Toplevel, Func{Exception, bool})"/>
-    ///     into a single
-    ///     call. An application cam use <see cref="Run{T}"/> without explicitly calling
-    ///     <see cref="Init(IConsoleDriver,string)"/>.
-    /// </para>
-    /// <param name="driver">
-    ///     The <see cref="IConsoleDriver"/> to use. If neither <paramref name="driver"/> or
-    ///     <paramref name="driverName"/> are specified the default driver for the platform will be used.
-    /// </param>
-    /// <param name="driverName">
-    ///     The driver name (e.g. "dotnet", "windows", "fake", or "unix") of the
-    ///     <see cref="IConsoleDriver"/> to use. If neither <paramref name="driver"/> or <paramref name="driverName"/> are
-    ///     specified the default driver for the platform will be used.
-    /// </param>
-    [RequiresUnreferencedCode ("AOT")]
-    [RequiresDynamicCode ("AOT")]
-    public void Init (IConsoleDriver? driver = null, string? driverName = null);
+    /// <summary>
+    ///     Raised when <see cref="Begin(Toplevel)"/> has been called and has created a new <see cref="SessionToken"/>.
+    /// </summary>
+    /// <remarks>
+    ///     If <see cref="StopAfterFirstIteration"/> is <see langword="true"/>, callers to <see cref="Begin(Toplevel)"/>
+    ///     must also subscribe to <see cref="SessionEnded"/> and manually dispose of the <see cref="SessionToken"/> token
+    ///     when the application is done.
+    /// </remarks>
+    public event EventHandler<SessionTokenEventArgs>? SessionBegun;
 
-    /// <summary>Runs <paramref name="action"/> on the main UI loop thread</summary>
-    /// <param name="action">the action to be invoked on the main processing thread.</param>
-    void Invoke (Action action);
+    /// <summary>
+    ///     Raised when <see cref="End(SessionToken)"/> was called and the session is stopping. The event args contain a
+    ///     reference to the <see cref="Toplevel"/>
+    ///     that was active during the session. This can be used to ensure the Toplevel is disposed of properly.
+    /// </summary>
+    /// <remarks>
+    ///     If <see cref="StopAfterFirstIteration"/> is <see langword="true"/>, callers to <see cref="Begin(Toplevel)"/>
+    ///     must also subscribe to <see cref="SessionEnded"/> and manually dispose of the <see cref="SessionToken"/> token
+    ///     when the application is done.
+    /// </remarks>
+    public event EventHandler<ToplevelEventArgs>? SessionEnded;
+
+    #endregion Begin->Run->Iteration->Stop->End
+
+    #region Toplevel Management
+
+    /// <summary>Gets or sets the current Toplevel.</summary>
+    /// <remarks>
+    ///     <para>
+    ///         This is set by <see cref="Begin(Toplevel)"/> and cleared by <see cref="End(SessionToken)"/>.
+    ///     </para>
+    /// </remarks>
+    Toplevel? Top { get; set; }
+
+    /// <summary>Gets the stack of all Toplevels.</summary>
+    /// <remarks>
+    ///     <para>
+    ///         Toplevels are added to this stack by <see cref="Begin(Toplevel)"/> and removed by
+    ///         <see cref="End(SessionToken)"/>.
+    ///     </para>
+    /// </remarks>
+    ConcurrentStack<Toplevel> TopLevels { get; }
 
     /// <summary>
-    ///     <see langword="true"/> if implementation is 'old'. <see langword="false"/> if implementation
-    ///     is cutting edge.
+    ///     Caches the Toplevel associated with the current Session.
     /// </summary>
-    bool IsLegacy { get; }
+    /// <remarks>
+    ///     Used internally to optimize Toplevel state transitions.
+    /// </remarks>
+    Toplevel? CachedSessionTokenToplevel { get; set; }
 
-    /// <summary>Removes a previously scheduled timeout</summary>
-    /// <remarks>The token parameter is the value returned by <see cref="AddTimeout"/>.</remarks>
-    /// <returns>
-    ///     <see langword="true"/>
-    ///     if the timeout is successfully removed; otherwise,
-    ///     <see langword="false"/>
-    ///     .
-    ///     This method also returns
-    ///     <see langword="false"/>
-    ///     if the timeout is not found.
-    /// </returns>
-    bool RemoveTimeout (object token);
+    #endregion Toplevel Management
+
+    #region Screen and Driver
 
-    /// <summary>Stops the provided <see cref="Toplevel"/>, causing or the <paramref name="top"/> if provided.</summary>
-    /// <param name="top">The <see cref="Toplevel"/> to stop.</param>
+    /// <summary>Gets or sets the console driver being used.</summary>
     /// <remarks>
-    ///     <para>This will cause <see cref="Application.Run(Toplevel, Func{Exception, bool})"/> to return.</para>
     ///     <para>
-    ///         Calling <see cref="RequestStop(Toplevel)"/> is equivalent to setting the <see cref="Toplevel.Running"/>
-    ///         property on the currently running <see cref="Toplevel"/> to false.
+    ///         Set by <see cref="Init"/> based on the driver parameter or platform default.
     ///     </para>
     /// </remarks>
-    void RequestStop (Toplevel? top);
+    IDriver? Driver { get; set; }
 
     /// <summary>
-    ///     Runs the application by creating a <see cref="Toplevel"/> object and calling
-    ///     <see cref="Run(Toplevel, Func{Exception, bool})"/>.
+    ///     Gets or sets whether <see cref="Driver"/> will be forced to output only the 16 colors defined in
+    ///     <see cref="ColorName16"/>. The default is <see langword="false"/>, meaning 24-bit (TrueColor) colors will be
+    ///     output as long as the selected <see cref="IDriver"/> supports TrueColor.
+    /// </summary>
+    bool Force16Colors { get; set; }
+
+    /// <summary>
+    ///     Forces the use of the specified driver (one of "fake", "dotnet", "windows", or "unix"). If not
+    ///     specified, the driver is selected based on the platform.
+    /// </summary>
+    string ForceDriver { get; set; }
+
+    /// <summary>
+    ///     Gets or sets the size of the screen. By default, this is the size of the screen as reported by the
+    ///     <see cref="IDriver"/>.
     /// </summary>
     /// <remarks>
-    ///     <para>Calling <see cref="Init"/> first is not needed as this function will initialize the application.</para>
     ///     <para>
-    ///         <see cref="Shutdown"/> must be called when the application is closing (typically after Run> has returned) to
-    ///         ensure resources are cleaned up and terminal settings restored.
+    ///         If the <see cref="IDriver"/> has not been initialized, this will return a default size of 2048x2048; useful
+    ///         for unit tests.
     ///     </para>
+    /// </remarks>
+    Rectangle Screen { get; set; }
+
+    /// <summary>Raised when the terminal's size changed. The new size of the terminal is provided.</summary>
+    /// <remarks>
     ///     <para>
-    ///         The caller is responsible for disposing the object returned by this method.
+    ///         This event is raised when the driver detects a screen size change. The event provides the new screen
+    ///         rectangle.
     ///     </para>
     /// </remarks>
-    /// <returns>The created <see cref="Toplevel"/> object. The caller is responsible for disposing this object.</returns>
-    [RequiresUnreferencedCode ("AOT")]
-    [RequiresDynamicCode ("AOT")]
-    public Toplevel Run (Func<Exception, bool>? errorHandler = null, IConsoleDriver? driver = null);
+    public event EventHandler<EventArgs<Rectangle>>? ScreenChanged;
 
     /// <summary>
-    ///     Runs the application by creating a <see cref="Toplevel"/>-derived object of type <c>T</c> and calling
-    ///     <see cref="Run(Toplevel, Func{Exception, bool})"/>.
+    ///     Gets or sets whether the screen will be cleared, and all Views redrawn, during the next Application iteration.
     /// </summary>
     /// <remarks>
-    ///     <para>Calling <see cref="Init"/> first is not needed as this function will initialize the application.</para>
     ///     <para>
-    ///         <see cref="Shutdown"/> must be called when the application is closing (typically after Run> has returned) to
-    ///         ensure resources are cleaned up and terminal settings restored.
+    ///         This is typically set to <see langword="true"/> when a View's <see cref="View.Frame"/> changes and that view
+    ///         has no SuperView (e.g. when <see cref="Top"/> is moved or resized).
     ///     </para>
     ///     <para>
-    ///         The caller is responsible for disposing the object returned by this method.
+    ///         Automatically reset to <see langword="false"/> after <see cref="LayoutAndDraw"/> processes it.
     ///     </para>
     /// </remarks>
-    /// <param name="errorHandler"></param>
-    /// <param name="driver">
-    ///     The <see cref="IConsoleDriver"/> to use. If not specified the default driver for the platform will
-    ///     be used. Must be
-    ///     <see langword="null"/> if <see cref="Init"/> has already been called.
-    /// </param>
-    /// <returns>The created T object. The caller is responsible for disposing this object.</returns>
-    [RequiresUnreferencedCode ("AOT")]
-    [RequiresDynamicCode ("AOT")]
-    public T Run<T> (Func<Exception, bool>? errorHandler = null, IConsoleDriver? driver = null)
-        where T : Toplevel, new();
+    bool ClearScreenNextIteration { get; set; }
 
-    /// <summary>Runs the Application using the provided <see cref="Toplevel"/> view.</summary>
+    /// <summary>
+    ///     Collection of sixel images to write out to screen when updating.
+    ///     Only add to this collection if you are sure terminal supports sixel format.
+    /// </summary>
+    List<SixelToRender> Sixel { get; }
+
+    #endregion Screen and Driver
+
+    #region Layout and Drawing
+
+    /// <summary>
+    ///     Causes any Toplevels that need layout to be laid out, then draws any Toplevels that need display. Only Views
+    ///     that need to be laid out (see <see cref="View.NeedsLayout"/>) will be laid out. Only Views that need to be drawn
+    ///     (see <see cref="View.NeedsDraw"/>) will be drawn.
+    /// </summary>
+    /// <param name="forceRedraw">
+    ///     If <see langword="true"/> the entire View hierarchy will be redrawn. The default is <see langword="false"/> and
+    ///     should only be overridden for testing.
+    /// </param>
     /// <remarks>
     ///     <para>
-    ///         This method is used to start processing events for the main application, but it is also used to run other
-    ///         modal <see cref="View"/>s such as <see cref="Dialog"/> boxes.
+    ///         This method is called automatically each main loop iteration when any views need layout or drawing.
     ///     </para>
     ///     <para>
-    ///         To make a <see cref="Run(Toplevel,System.Func{System.Exception,bool})"/> stop execution, call
-    ///         <see cref="Application.RequestStop"/>.
-    ///     </para>
-    ///     <para>
-    ///         Calling <see cref="Run(Toplevel,System.Func{System.Exception,bool})"/> is equivalent to calling
-    ///         <see cref="Application.Begin(Toplevel)"/>, followed by <see cref="Application.RunLoop(RunState)"/>, and then
-    ///         calling
-    ///         <see cref="Application.End(RunState)"/>.
+    ///         If <see cref="ClearScreenNextIteration"/> is <see langword="true"/>, the screen will be cleared before
+    ///         drawing and the flag will be reset to <see langword="false"/>.
     ///     </para>
+    /// </remarks>
+    public void LayoutAndDraw (bool forceRedraw = false);
+
+    /// <summary>
+    ///     Calls <see cref="View.PositionCursor"/> on the most focused view.
+    /// </summary>
+    /// <remarks>
+    ///     <para>Does nothing if there is no most focused view.</para>
     ///     <para>
-    ///         Alternatively, to have a program control the main loop and process events manually, call
-    ///         <see cref="Application.Begin(Toplevel)"/> to set things up manually and then repeatedly call
-    ///         <see cref="Application.RunLoop(RunState)"/> with the wait parameter set to false. By doing this the
-    ///         <see cref="Application.RunLoop(RunState)"/> method will only process any pending events, timers handlers and
-    ///         then
-    ///         return control immediately.
+    ///         If the most focused view is not visible within its superview, the cursor will be hidden.
     ///     </para>
+    /// </remarks>
+    /// <returns><see langword="true"/> if a view positioned the cursor and the position is visible.</returns>
+    public bool PositionCursor ();
+
+    #endregion Layout and Drawing
+
+    #region Navigation and Popover
+
+    /// <summary>Gets or sets the popover manager.</summary>
+    /// <remarks>
     ///     <para>
-    ///         When using <see cref="Run{T}"/> or
-    ///         <see cref="Run(System.Func{System.Exception,bool},IConsoleDriver)"/>
-    ///         <see cref="Init"/> will be called automatically.
+    ///         Manages application-level popover views. Initialized during <see cref="Init"/>.
     ///     </para>
+    /// </remarks>
+    ApplicationPopover? Popover { get; set; }
+
+    /// <summary>Gets or sets the navigation manager.</summary>
+    /// <remarks>
     ///     <para>
-    ///         RELEASE builds only: When <paramref name="errorHandler"/> is <see langword="null"/> any exceptions will be
-    ///         rethrown. Otherwise, if <paramref name="errorHandler"/> will be called. If <paramref name="errorHandler"/>
-    ///         returns <see langword="true"/> the <see cref="Application.RunLoop(RunState)"/> will resume; otherwise this
-    ///         method will
-    ///         exit.
+    ///         Manages focus navigation and tracking of the most focused view. Initialized during <see cref="Init"/>.
     ///     </para>
     /// </remarks>
-    /// <param name="view">The <see cref="Toplevel"/> to run as a modal.</param>
-    /// <param name="errorHandler">
-    ///     RELEASE builds only: Handler for any unhandled exceptions (resumes when returns true,
-    ///     rethrows when null).
-    /// </param>
-    public void Run (Toplevel view, Func<Exception, bool>? errorHandler = null);
+    ApplicationNavigation? Navigation { get; set; }
 
-    /// <summary>Shutdown an application initialized with <see cref="Init"/>.</summary>
+    #endregion Navigation and Popover
+
+    #region Timeouts
+
+    /// <summary>Adds a timeout to the application.</summary>
+    /// <param name="time">The time span to wait before invoking the callback.</param>
+    /// <param name="callback">
+    ///     The callback to invoke. If it returns <see langword="true"/>, the timeout will be reset and repeat. If it
+    ///     returns <see langword="false"/>, the timeout will stop and be removed.
+    /// </param>
+    /// <returns>
+    ///     A token that can be used to stop the timeout by calling <see cref="RemoveTimeout(object)"/>.
+    /// </returns>
     /// <remarks>
-    ///     Shutdown must be called for every call to <see cref="Init"/> or
-    ///     <see cref="Application.Run(Toplevel, Func{Exception, bool})"/> to ensure all resources are cleaned
-    ///     up (Disposed)
-    ///     and terminal settings are restored.
+    ///     <para>
+    ///         When the time specified passes, the callback will be invoked on the main UI thread.
+    ///     </para>
     /// </remarks>
-    public void Shutdown ();
+    object AddTimeout (TimeSpan time, Func<bool> callback);
+
+    /// <summary>Removes a previously scheduled timeout.</summary>
+    /// <param name="token">The token returned by <see cref="AddTimeout"/>.</param>
+    /// <returns>
+    ///     <see langword="true"/> if the timeout is successfully removed; otherwise, <see langword="false"/>.
+    ///     This method also returns <see langword="false"/> if the timeout is not found.
+    /// </returns>
+    bool RemoveTimeout (object token);
 
     /// <summary>
     ///     Handles recurring events. These are invoked on the main UI thread - allowing for
     ///     safe updates to <see cref="View"/> instances.
     /// </summary>
+    /// <remarks>
+    ///     <para>
+    ///         Provides low-level access to the timeout management system. Most applications should use
+    ///         <see cref="AddTimeout"/> and <see cref="RemoveTimeout"/> instead.
+    ///     </para>
+    /// </remarks>
     ITimedEvents? TimedEvents { get; }
+
+    #endregion Timeouts
 }

Terminal.Gui/App/IterationEventArgs.cs

@@ -1,5 +1,5 @@
 namespace Terminal.Gui.App;
 
-/// <summary>Event arguments for the <see cref="Application.Iteration"/> event.</summary>
+/// <summary>Event arguments for the <see cref="IApplication.Iteration"/> event.</summary>
 public class IterationEventArgs : EventArgs
 { }

Terminal.Gui/App/Keyboard/IKeyboard.cs

@@ -17,7 +17,7 @@ public interface IKeyboard
     IApplication? Application { get; set; }
 
     /// <summary>
-    ///     Called when the user presses a key (by the <see cref="IConsoleDriver"/>). Raises the cancelable
+    ///     Called when the user presses a key (by the <see cref="IDriver"/>). Raises the cancelable
     ///     <see cref="KeyDown"/> event, then calls <see cref="View.NewKeyDownEvent"/> on all top level views, and finally
     ///     if the key was not handled, invokes any Application-scoped <see cref="KeyBindings"/>.
     /// </summary>
@@ -27,7 +27,7 @@ public interface IKeyboard
     bool RaiseKeyDownEvent (Key key);
 
     /// <summary>
-    ///     Called when the user releases a key (by the <see cref="IConsoleDriver"/>). Raises the cancelable
+    ///     Called when the user releases a key (by the <see cref="IDriver"/>). Raises the cancelable
     ///     <see cref="KeyUp"/>
     ///     event
     ///     then calls <see cref="View.NewKeyUpEvent"/> on all top level views. Called after <see cref="RaiseKeyDownEvent"/>.

Terminal.Gui/App/Keyboard/KeyboardImpl.cs

@@ -1,4 +1,6 @@
 #nullable enable
+using System.Diagnostics;
+
 namespace Terminal.Gui.App;
 
 /// <summary>
@@ -114,7 +116,8 @@ internal class KeyboardImpl : IKeyboard
     /// <inheritdoc/>
     public bool RaiseKeyDownEvent (Key key)
     {
-        Logging.Debug ($"{key}");
+        //ebug.Assert (App.Application.MainThreadId == Thread.CurrentThread.ManagedThreadId);
+        //Logging.Debug ($"{key}");
 
         // TODO: Add a way to ignore certain keys, esp for debugging.
         //#if DEBUG

Terminal.Gui/App/MainLoop/ApplicationMainLoop.cs

@@ -1,7 +1,8 @@
 #nullable enable
-using Terminal.Gui.Drivers;
+using System;
 using System.Collections.Concurrent;
 using System.Diagnostics;
+using Terminal.Gui.Drivers;
 
 namespace Terminal.Gui.App;
 
@@ -19,15 +20,15 @@ namespace Terminal.Gui.App;
 ///         <item>Throttling iterations to respect <see cref="Application.MaximumIterationsPerSecond"/></item>
 ///     </list>
 /// </remarks>
-/// <typeparam name="T">Type of raw input events, e.g. <see cref="ConsoleKeyInfo"/> for .NET driver</typeparam>
-public class ApplicationMainLoop<T> : IApplicationMainLoop<T>
+/// <typeparam name="TInputRecord">Type of raw input events, e.g. <see cref="ConsoleKeyInfo"/> for .NET driver</typeparam>
+public class ApplicationMainLoop<TInputRecord> : IApplicationMainLoop<TInputRecord> where TInputRecord : struct
 {
     private ITimedEvents? _timedEvents;
-    private ConcurrentQueue<T>? _inputBuffer;
+    private ConcurrentQueue<TInputRecord>? _inputQueue;
     private IInputProcessor? _inputProcessor;
-    private IConsoleOutput? _out;
+    private IOutput? _output;
     private AnsiRequestScheduler? _ansiRequestScheduler;
-    private IWindowSizeMonitor? _windowSizeMonitor;
+    private ISizeMonitor? _sizeMonitor;
 
     /// <inheritdoc/>
     public ITimedEvents TimedEvents
@@ -40,13 +41,13 @@ public class ApplicationMainLoop<T> : IApplicationMainLoop<T>
 
     /// <summary>
     ///     The input events thread-safe collection. This is populated on separate
-    ///     thread by a <see cref="IConsoleInput{T}"/>. Is drained as part of each
-    ///     <see cref="Iteration"/>
+    ///     thread by a <see cref="IInput{T}"/>. Is drained as part of each
+    ///     <see cref="Iteration"/> on the main loop thread.
     /// </summary>
-    public ConcurrentQueue<T> InputBuffer
+    public ConcurrentQueue<TInputRecord> InputQueue
     {
-        get => _inputBuffer ?? throw new NotInitializedException (nameof (InputBuffer));
-        private set => _inputBuffer = value;
+        get => _inputQueue ?? throw new NotInitializedException (nameof (InputQueue));
+        private set => _inputQueue = value;
     }
 
     /// <inheritdoc/>
@@ -57,13 +58,13 @@ public class ApplicationMainLoop<T> : IApplicationMainLoop<T>
     }
 
     /// <inheritdoc/>
-    public IOutputBuffer OutputBuffer { get; } = new OutputBuffer ();
+    public IOutputBuffer OutputBuffer { get; } = new OutputBufferImpl ();
 
     /// <inheritdoc/>
-    public IConsoleOutput Out
+    public IOutput Output
     {
-        get => _out ?? throw new NotInitializedException (nameof (Out));
-        private set => _out = value;
+        get => _output ?? throw new NotInitializedException (nameof (Output));
+        private set => _output = value;
     }
 
     /// <inheritdoc/>
@@ -74,10 +75,10 @@ public class ApplicationMainLoop<T> : IApplicationMainLoop<T>
     }
 
     /// <inheritdoc/>
-    public IWindowSizeMonitor WindowSizeMonitor
+    public ISizeMonitor SizeMonitor
     {
-        get => _windowSizeMonitor ?? throw new NotInitializedException (nameof (WindowSizeMonitor));
-        private set => _windowSizeMonitor = value;
+        get => _sizeMonitor ?? throw new NotInitializedException (nameof (SizeMonitor));
+        private set => _sizeMonitor = value;
     }
 
     /// <summary>
@@ -85,12 +86,6 @@ public class ApplicationMainLoop<T> : IApplicationMainLoop<T>
     /// </summary>
     public IToplevelTransitionManager ToplevelTransitionManager = new ToplevelTransitionManager ();
 
-    /// <summary>
-    ///     Determines how to get the current system type, adjust
-    ///     in unit tests to simulate specific timings.
-    /// </summary>
-    public Func<DateTime> Now { get; set; } = () => DateTime.Now;
-
     /// <summary>
     ///     Initializes the class with the provided subcomponents
     /// </summary>
@@ -101,34 +96,34 @@ public class ApplicationMainLoop<T> : IApplicationMainLoop<T>
     /// <param name="componentFactory"></param>
     public void Initialize (
         ITimedEvents timedEvents,
-        ConcurrentQueue<T> inputBuffer,
+        ConcurrentQueue<TInputRecord> inputBuffer,
         IInputProcessor inputProcessor,
-        IConsoleOutput consoleOutput,
-        IComponentFactory<T> componentFactory
+        IOutput consoleOutput,
+        IComponentFactory<TInputRecord> componentFactory
     )
     {
-        InputBuffer = inputBuffer;
-        Out = consoleOutput;
+        InputQueue = inputBuffer;
+        Output = consoleOutput;
         InputProcessor = inputProcessor;
 
         TimedEvents = timedEvents;
         AnsiRequestScheduler = new (InputProcessor.GetParser ());
 
-        WindowSizeMonitor = componentFactory.CreateWindowSizeMonitor (Out, OutputBuffer);
+        OutputBuffer.SetSize (consoleOutput.GetSize ().Width, consoleOutput.GetSize ().Height);
+        SizeMonitor = componentFactory.CreateSizeMonitor (Output, OutputBuffer);
     }
 
     /// <inheritdoc/>
     public void Iteration ()
     {
-
         Application.RaiseIteration ();
 
-        DateTime dt = Now ();
+        DateTime dt = DateTime.Now;
         int timeAllowed = 1000 / Math.Max(1,(int)Application.MaximumIterationsPerSecond);
 
         IterationImpl ();
 
-        TimeSpan took = Now () - dt;
+        TimeSpan took = DateTime.Now - dt;
         TimeSpan sleepFor = TimeSpan.FromMilliseconds (timeAllowed) - took;
 
         Logging.TotalIterationMetric.Record (took.Milliseconds);
@@ -141,6 +136,7 @@ public class ApplicationMainLoop<T> : IApplicationMainLoop<T>
 
     internal void IterationImpl ()
     {
+        // Pull any input events from the input queue and process them
         InputProcessor.ProcessQueue ();
 
         ToplevelTransitionManager.RaiseReadyEventIfNeeded ();
@@ -152,7 +148,7 @@ public class ApplicationMainLoop<T> : IApplicationMainLoop<T>
                                      || AnySubViewsNeedDrawn (Application.Top)
                                      || (Application.Mouse.MouseGrabView != null && AnySubViewsNeedDrawn (Application.Mouse.MouseGrabView));
 
-            bool sizeChanged = WindowSizeMonitor.Poll ();
+            bool sizeChanged = SizeMonitor.Poll ();
 
             if (needsDrawOrLayout || sizeChanged)
             {
@@ -160,9 +156,9 @@ public class ApplicationMainLoop<T> : IApplicationMainLoop<T>
 
                 Application.LayoutAndDraw (true);
 
-                Out.Write (OutputBuffer);
+                Output.Write (OutputBuffer);
 
-                Out.SetCursorVisibility (CursorVisibility.Default);
+                Output.SetCursorVisibility (CursorVisibility.Default);
             }
 
             SetCursor ();
@@ -191,12 +187,12 @@ public class ApplicationMainLoop<T> : IApplicationMainLoop<T>
             // Translate to screen coordinates
             to = mostFocused.ViewportToScreen (to.Value);
 
-            Out.SetCursorPosition (to.Value.X, to.Value.Y);
-            Out.SetCursorVisibility (mostFocused.CursorVisibility);
+            Output.SetCursorPosition (to.Value.X, to.Value.Y);
+            Output.SetCursorVisibility (mostFocused.CursorVisibility);
         }
         else
         {
-            Out.SetCursorVisibility (CursorVisibility.Invisible);
+            Output.SetCursorVisibility (CursorVisibility.Invisible);
         }
     }
 

Terminal.Gui/App/MainLoop/IApplicationMainLoop.cs

@@ -15,27 +15,27 @@ namespace Terminal.Gui.App;
 ///         <item>Rendering UI updates to the console</item>
 ///     </list>
 /// </remarks>
-/// <typeparam name="T">Type of raw input events processed by the loop, e.g. <see cref="ConsoleKeyInfo"/> for cross-platform .NET driver</typeparam>
-public interface IApplicationMainLoop<T> : IDisposable
+/// <typeparam name="TInputRecord">Type of raw input events processed by the loop, e.g. <see cref="ConsoleKeyInfo"/> for cross-platform .NET driver</typeparam>
+public interface IApplicationMainLoop<TInputRecord> : IDisposable where TInputRecord : struct
 {
     /// <summary>
-    ///     Gets the class responsible for servicing user timeouts
+    ///     Gets the <see cref="ITimedEvents"/> implementation that manages user-defined timeouts and periodic events.
     /// </summary>
     public ITimedEvents TimedEvents { get; }
 
     /// <summary>
-    ///     Gets the class responsible for writing final rendered output to the console
+    ///     Gets the <see cref="IOutputBuffer"/> representing the desired screen state for console rendering.
     /// </summary>
     public IOutputBuffer OutputBuffer { get; }
 
     /// <summary>
-    ///     Class for writing output to the console.
+    ///     Gets the <see cref="IOutput"/> implementation responsible for rendering the <see cref="OutputBuffer"/> to the console using platform specific methods.
     /// </summary>
-    public IConsoleOutput Out { get; }
+    public IOutput Output { get; }
 
     /// <summary>
-    ///     Gets the class responsible for processing buffered console input and translating
-    ///     it into events on the UI thread.
+    ///     Gets <see cref="InputProcessor"/> implementation that processes the mouse and keyboard input populated by <see cref="IInput{TInputRecord}"/>
+    ///     implementations on the input thread and translating to events on the UI thread.
     /// </summary>
     public IInputProcessor InputProcessor { get; }
 
@@ -46,24 +46,59 @@ public interface IApplicationMainLoop<T> : IDisposable
     public AnsiRequestScheduler AnsiRequestScheduler { get; }
 
     /// <summary>
-    ///     Gets the class responsible for determining the current console size
+    ///     Gets the <see cref="ISizeMonitor"/> implementation that tracks terminal size changes.
     /// </summary>
-    public IWindowSizeMonitor WindowSizeMonitor { get; }
+    public ISizeMonitor SizeMonitor { get; }
 
     /// <summary>
-    ///     Initializes the loop with a buffer from which data can be read
+    ///     Initializes the main loop with its required dependencies.
     /// </summary>
-    /// <param name="timedEvents"></param>
-    /// <param name="inputBuffer"></param>
-    /// <param name="inputProcessor"></param>
-    /// <param name="consoleOutput"></param>
-    /// <param name="componentFactory"></param>
+    /// <param name="timedEvents">
+    ///     The <see cref="ITimedEvents"/> implementation for managing user-defined timeouts and periodic callbacks
+    ///     (e.g., <see cref="Application.AddTimeout"/>).
+    /// </param>
+    /// <param name="inputQueue">
+    ///     The thread-safe queue containing raw input events populated by <see cref="IInput{TInputRecord}"/> on
+    ///     the input thread. This queue is drained by <see cref="InputProcessor"/> during each <see cref="Iteration"/>.
+    /// </param>
+    /// <param name="inputProcessor">
+    ///     The <see cref="IInputProcessor"/> that translates raw input records (e.g., <see cref="ConsoleKeyInfo"/>) 
+    ///     into Terminal.Gui events (<see cref="Key"/>, <see cref="MouseEventArgs"/>) and raises them on the main UI thread.
+    /// </param>
+    /// <param name="output">
+    ///     The <see cref="IOutput"/> implementation responsible for rendering the <see cref="OutputBuffer"/> to the
+    ///     console using platform-specific methods (e.g., Win32 APIs, ANSI escape sequences).
+    /// </param>
+    /// <param name="componentFactory">
+    ///     The factory for creating driver-specific components. Used here to create the <see cref="ISizeMonitor"/>
+    ///     that tracks terminal size changes.
+    /// </param>
+    /// <remarks>
+    ///     <para>
+    ///         This method is called by <see cref="MainLoopCoordinator{TInputRecord}"/> during application startup
+    ///         to wire up all the components needed for the main loop to function. It must be called before
+    ///         <see cref="Iteration"/> can be invoked.
+    ///     </para>
+    ///     <para>
+    ///         <b>Initialization order:</b>
+    ///     </para>
+    ///     <list type="number">
+    ///         <item>Store references to <paramref name="timedEvents"/>, <paramref name="inputQueue"/>, 
+    ///               <paramref name="inputProcessor"/>, and <paramref name="output"/></item>
+    ///         <item>Create <see cref="AnsiRequestScheduler"/> for managing ANSI requests/responses</item>
+    ///         <item>Initialize <see cref="OutputBuffer"/> size to match current console dimensions</item>
+    ///         <item>Create <see cref="ISizeMonitor"/> using the <paramref name="componentFactory"/></item>
+    ///     </list>
+    ///     <para>
+    ///         After initialization, the main loop is ready to process events via <see cref="Iteration"/>.
+    ///     </para>
+    /// </remarks>
     void Initialize (
         ITimedEvents timedEvents,
-        ConcurrentQueue<T> inputBuffer,
+        ConcurrentQueue<TInputRecord> inputQueue,
         IInputProcessor inputProcessor,
-        IConsoleOutput consoleOutput,
-        IComponentFactory<T> componentFactory
+        IOutput output,
+        IComponentFactory<TInputRecord> componentFactory
     );
 
     /// <summary>

Terminal.Gui/App/MainLoop/IMainLoopCoordinator.cs

@@ -8,7 +8,6 @@
 ///     <list type="bullet">
 ///         <item>Starting the asynchronous input reading thread</item>
 ///         <item>Initializing the main UI loop on the application thread</item>
-///         <item>Building the <see cref="IConsoleDriver"/> facade</item>
 ///         <item>Coordinating clean shutdown of both threads</item>
 ///     </list>
 /// </remarks>
@@ -26,7 +25,7 @@ public interface IMainLoopCoordinator
     ///     </list>
     /// </remarks>
     /// <returns>A task that completes when initialization is done</returns>
-    public Task StartAsync ();
+    public Task StartInputTaskAsync ();
 
     /// <summary>
     ///     Stops the input thread and performs cleanup.

Terminal.Gui/App/MainLoop/MainLoopCoordinator.cs

@@ -1,6 +1,4 @@
 using System.Collections.Concurrent;
-using Terminal.Gui.Drivers;
-using Microsoft.Extensions.Logging;
 
 namespace Terminal.Gui.App;
 
@@ -15,50 +13,52 @@ namespace Terminal.Gui.App;
 ///     </para>
 ///     <para>This class is designed to be managed by <see cref="ApplicationImpl"/></para>
 /// </summary>
-/// <typeparam name="T">Type of raw input events, e.g. <see cref="ConsoleKeyInfo"/> for .NET driver</typeparam>
-internal class MainLoopCoordinator<T> : IMainLoopCoordinator
+/// <typeparam name="TInputRecord">Type of raw input events, e.g. <see cref="ConsoleKeyInfo"/> for .NET driver</typeparam>
+internal class MainLoopCoordinator<TInputRecord> : IMainLoopCoordinator where TInputRecord : struct
 {
-    private readonly ConcurrentQueue<T> _inputBuffer;
-    private readonly IInputProcessor _inputProcessor;
-    private readonly IApplicationMainLoop<T> _loop;
-    private readonly IComponentFactory<T> _componentFactory;
-    private readonly CancellationTokenSource _tokenSource = new ();
-    private IConsoleInput<T> _input;
-    private IConsoleOutput _output;
-    private readonly object _oLockInitialization = new ();
-    private ConsoleDriverFacade<T> _facade;
-    private Task _inputTask;
-    private readonly ITimedEvents _timedEvents;
-
-    private readonly SemaphoreSlim _startupSemaphore = new (0, 1);
-
     /// <summary>
     ///     Creates a new coordinator that will manage the main UI loop and input thread.
     /// </summary>
     /// <param name="timedEvents">Handles scheduling and execution of user timeout callbacks</param>
-    /// <param name="inputBuffer">Thread-safe queue for buffering raw console input</param>
+    /// <param name="inputQueue">Thread-safe queue for buffering raw console input</param>
     /// <param name="loop">The main application loop instance</param>
     /// <param name="componentFactory">Factory for creating driver-specific components (input, output, etc.)</param>
     public MainLoopCoordinator (
         ITimedEvents timedEvents,
-        ConcurrentQueue<T> inputBuffer,
-        IApplicationMainLoop<T> loop,
-        IComponentFactory<T> componentFactory
+        ConcurrentQueue<TInputRecord> inputQueue,
+        IApplicationMainLoop<TInputRecord> loop,
+        IComponentFactory<TInputRecord> componentFactory
     )
     {
         _timedEvents = timedEvents;
-        _inputBuffer = inputBuffer;
-        _inputProcessor = componentFactory.CreateInputProcessor (_inputBuffer);
+        _inputQueue = inputQueue;
+        _inputProcessor = componentFactory.CreateInputProcessor (_inputQueue);
         _loop = loop;
         _componentFactory = componentFactory;
     }
 
+    private readonly IApplicationMainLoop<TInputRecord> _loop;
+    private readonly IComponentFactory<TInputRecord> _componentFactory;
+    private readonly CancellationTokenSource _runCancellationTokenSource = new ();
+    private readonly ConcurrentQueue<TInputRecord> _inputQueue;
+    private readonly IInputProcessor _inputProcessor;
+    private readonly object _oLockInitialization = new ();
+    private readonly ITimedEvents _timedEvents;
+
+    private readonly SemaphoreSlim _startupSemaphore = new (0, 1);
+    private IInput<TInputRecord> _input;
+    private Task _inputTask;
+    private IOutput _output;
+    private DriverImpl _driver;
+
+    private bool _stopCalled;
+
     /// <summary>
     ///     Starts the input loop thread in separate task (returning immediately).
     /// </summary>
-    public async Task StartAsync ()
+    public async Task StartInputTaskAsync ()
     {
-        Logging.Logger.LogInformation ("Main Loop Coordinator booting...");
+        Logging.Trace ("Booting... ()");
 
         _inputTask = Task.Run (RunInput);
 
@@ -80,100 +80,117 @@ internal class MainLoopCoordinator<T> : IMainLoopCoordinator
                 throw _inputTask.Exception;
             }
 
-            Logging.Logger.LogCritical("Input loop exited during startup instead of entering read loop properly (i.e. and blocking)");
+            Logging.Critical ("Input loop exited during startup instead of entering read loop properly (i.e. and blocking)");
         }
 
-        Logging.Logger.LogInformation ("Main Loop Coordinator booting complete");
+        Logging.Trace ("Booting complete");
     }
 
-    private void RunInput ()
+    /// <inheritdoc/>
+    public void RunIteration ()
     {
-        try
-        {
-            lock (_oLockInitialization)
-            {
-                // Instance must be constructed on the thread in which it is used.
-                _input = _componentFactory.CreateInput ();
-                _input.Initialize (_inputBuffer);
-
-                BuildFacadeIfPossible ();
-            }
-
-            try
-            {
-                _input.Run (_tokenSource.Token);
-            }
-            catch (OperationCanceledException)
-            { }
-
-            _input.Dispose ();
-        }
-        catch (Exception e)
+        lock (_oLockInitialization)
         {
-            Logging.Logger.LogCritical (e, "Input loop crashed");
-
-            throw;
+            _loop.Iteration ();
         }
+    }
 
+    /// <inheritdoc/>
+    public void Stop ()
+    {
+        // Ignore repeated calls to Stop - happens if user spams Application.Shutdown().
         if (_stopCalled)
         {
-            Logging.Logger.LogInformation ("Input loop exited cleanly");
-        }
-        else
-        {
-            Logging.Logger.LogCritical ("Input loop exited early (stop not called)");
+            return;
         }
-    }
 
-    /// <inheritdoc/>
-    public void RunIteration () { _loop.Iteration (); }
+        _stopCalled = true;
+
+        _runCancellationTokenSource.Cancel ();
+        _output.Dispose ();
+
+        // Wait for input infinite loop to exit
+        _inputTask.Wait ();
+    }
 
     private void BootMainLoop ()
     {
+        //Logging.Trace ($"_inputProcessor: {_inputProcessor}, _output: {_output}, _componentFactory: {_componentFactory}");
+
         lock (_oLockInitialization)
         {
             // Instance must be constructed on the thread in which it is used.
             _output = _componentFactory.CreateOutput ();
-            _loop.Initialize (_timedEvents, _inputBuffer, _inputProcessor, _output,_componentFactory);
+            _loop.Initialize (_timedEvents, _inputQueue, _inputProcessor, _output, _componentFactory);
 
-            BuildFacadeIfPossible ();
+            BuildDriverIfPossible ();
         }
     }
 
-    private void BuildFacadeIfPossible ()
+    private void BuildDriverIfPossible ()
     {
+
         if (_input != null && _output != null)
         {
-            _facade = new (
+            _driver = new (
                            _inputProcessor,
                            _loop.OutputBuffer,
                            _output,
                            _loop.AnsiRequestScheduler,
-                           _loop.WindowSizeMonitor);
+                           _loop.SizeMonitor);
 
-            Application.Driver = _facade;
+            Application.Driver = _driver;
 
             _startupSemaphore.Release ();
+            Logging.Trace ($"Driver: _input: {_input}, _output: {_output}");
         }
     }
 
-    private bool _stopCalled;
-
-    /// <inheritdoc/>
-    public void Stop ()
+    /// <summary>
+    ///     INTERNAL: Runs the IInput read loop on a new thread called the "Input Thread".
+    /// </summary>
+    private void RunInput ()
     {
-        // Ignore repeated calls to Stop - happens if user spams Application.Shutdown().
-        if (_stopCalled)
+        try
         {
-            return;
-        }
+            lock (_oLockInitialization)
+            {
+                // Instance must be constructed on the thread in which it is used.
+                _input = _componentFactory.CreateInput ();
+                _input.Initialize (_inputQueue);
 
-        _stopCalled = true;
+                // Wire up InputImpl reference for ITestableInput support
+                if (_inputProcessor is InputProcessorImpl<TInputRecord> impl)
+                {
+                    impl.InputImpl = _input;
+                }
 
-        _tokenSource.Cancel ();
-        _output.Dispose ();
+                BuildDriverIfPossible ();
+            }
 
-        // Wait for input infinite loop to exit
-        _inputTask.Wait ();
+            try
+            {
+                _input.Run (_runCancellationTokenSource.Token);
+            }
+            catch (OperationCanceledException)
+            { }
+
+            _input.Dispose ();
+        }
+        catch (Exception e)
+        {
+            Logging.Critical ($"Input loop crashed: {e}");
+
+            throw;
+        }
+
+        if (_stopCalled)
+        {
+            Logging.Information ("Input loop exited cleanly");
+        }
+        else
+        {
+            Logging.Critical ("Input loop exited early (stop not called)");
+        }
     }
 }

Terminal.Gui/App/Mouse/MouseImpl.cs

@@ -1,5 +1,6 @@
 #nullable enable
 using System.ComponentModel;
+using System.Diagnostics;
 
 namespace Terminal.Gui.App;
 
@@ -55,6 +56,7 @@ internal class MouseImpl : IMouse
     /// <inheritdoc/>
     public void RaiseMouseEvent (MouseEventArgs mouseEvent)
     {
+        //Debug.Assert (App.Application.MainThreadId == Thread.CurrentThread.ManagedThreadId);
         if (Application?.Initialized is true)
         {
             // LastMousePosition is only set if the application is initialized.
@@ -371,11 +373,11 @@ internal class MouseImpl : IMouse
                 Position = frameLoc,
                 Flags = mouseEvent.Flags,
                 ScreenPosition = mouseEvent.ScreenPosition,
-                View = deepestViewUnderMouse ?? MouseGrabView
+                View = MouseGrabView // Always set to the grab view. See Issue #4370
             };
 
             //System.Diagnostics.Debug.WriteLine ($"{nme.Flags};{nme.X};{nme.Y};{mouseGrabView}");
-            if (MouseGrabView?.NewMouseEvent (viewRelativeMouseEvent) is true)
+            if (MouseGrabView?.NewMouseEvent (viewRelativeMouseEvent) is true || viewRelativeMouseEvent.IsSingleClicked)
             {
                 return true;
             }

Terminal.Gui/App/RunStateEventArgs.cs

@@ -1,12 +0,0 @@
-namespace Terminal.Gui.App;
-
-/// <summary>Event arguments for events about <see cref="RunState"/></summary>
-public class RunStateEventArgs : EventArgs
-{
-    /// <summary>Creates a new instance of the <see cref="RunStateEventArgs"/> class</summary>
-    /// <param name="state"></param>
-    public RunStateEventArgs (RunState state) { State = state; }
-
-    /// <summary>The state being reported on by the event</summary>
-    public RunState State { get; }
-}

Terminal.Gui/App/RunState.cs → Terminal.Gui/App/SessionToken.cs

@@ -2,22 +2,22 @@
 
 namespace Terminal.Gui.App;
 
-/// <summary>The execution state for a <see cref="Toplevel"/> view.</summary>
-public class RunState : IDisposable
+/// <summary>Defines a session token for a running <see cref="Toplevel"/>.</summary>
+public class SessionToken : IDisposable
 {
-    /// <summary>Initializes a new <see cref="RunState"/> class.</summary>
+    /// <summary>Initializes a new <see cref="SessionToken"/> class.</summary>
     /// <param name="view"></param>
-    public RunState (Toplevel view) { Toplevel = view; }
+    public SessionToken (Toplevel view) { Toplevel = view; }
 
-    /// <summary>The <see cref="Toplevel"/> belonging to this <see cref="RunState"/>.</summary>
+    /// <summary>The <see cref="Toplevel"/> belonging to this <see cref="SessionToken"/>.</summary>
     public Toplevel Toplevel { get; internal set; }
 
-    /// <summary>Releases all resource used by the <see cref="RunState"/> object.</summary>
-    /// <remarks>Call <see cref="Dispose()"/> when you are finished using the <see cref="RunState"/>.</remarks>
+    /// <summary>Releases all resource used by the <see cref="SessionToken"/> object.</summary>
+    /// <remarks>Call <see cref="Dispose()"/> when you are finished using the <see cref="SessionToken"/>.</remarks>
     /// <remarks>
-    ///     <see cref="Dispose()"/> method leaves the <see cref="RunState"/> in an unusable state. After calling
-    ///     <see cref="Dispose()"/>, you must release all references to the <see cref="RunState"/> so the garbage collector can
-    ///     reclaim the memory that the <see cref="RunState"/> was occupying.
+    ///     <see cref="Dispose()"/> method leaves the <see cref="SessionToken"/> in an unusable state. After calling
+    ///     <see cref="Dispose()"/>, you must release all references to the <see cref="SessionToken"/> so the garbage collector can
+    ///     reclaim the memory that the <see cref="SessionToken"/> was occupying.
     /// </remarks>
     public void Dispose ()
     {
@@ -28,7 +28,7 @@ public class RunState : IDisposable
 #endif
     }
 
-    /// <summary>Releases all resource used by the <see cref="RunState"/> object.</summary>
+    /// <summary>Releases all resource used by the <see cref="SessionToken"/> object.</summary>
     /// <param name="disposing">If set to <see langword="true"/> we are disposing and should dispose held objects.</param>
     protected virtual void Dispose (bool disposing)
     {
@@ -38,7 +38,7 @@ public class RunState : IDisposable
             // But that is not correct becaue `Begin` didn't create the TopLevel, `Init` did; thus
             // disposing should be done by `Shutdown`, not `End`.
             throw new InvalidOperationException (
-                                                 "Toplevel must be null before calling Application.RunState.Dispose"
+                                                 "Toplevel must be null before calling Application.SessionToken.Dispose"
                                                 );
         }
     }
@@ -46,29 +46,29 @@ public class RunState : IDisposable
 #if DEBUG_IDISPOSABLE
 #pragma warning disable CS0419 // Ambiguous reference in cref attribute
     /// <summary>
-    ///     Gets whether <see cref="RunState.Dispose"/> was called on this RunState or not.
+    ///     Gets whether <see cref="SessionToken.Dispose"/> was called on this SessionToken or not.
     ///     For debug purposes to verify objects are being disposed properly.
     ///     Only valid when DEBUG_IDISPOSABLE is defined.
     /// </summary>
     public bool WasDisposed { get; private set; }
 
     /// <summary>
-    ///     Gets the number of times <see cref="RunState.Dispose"/> was called on this object.
+    ///     Gets the number of times <see cref="SessionToken.Dispose"/> was called on this object.
     ///     For debug purposes to verify objects are being disposed properly.
     ///     Only valid when DEBUG_IDISPOSABLE is defined.
     /// </summary>
     public int DisposedCount { get; private set; } = 0;
 
     /// <summary>
-    ///     Gets the list of RunState objects that have been created and not yet disposed.
-    ///     Note, this is a static property and will affect all RunState objects.
+    ///     Gets the list of SessionToken objects that have been created and not yet disposed.
+    ///     Note, this is a static property and will affect all SessionToken objects.
     ///     For debug purposes to verify objects are being disposed properly.
     ///     Only valid when DEBUG_IDISPOSABLE is defined.
     /// </summary>
-    public static ConcurrentBag<RunState> Instances { get; private set; } = [];
+    public static ConcurrentBag<SessionToken> Instances { get; private set; } = [];
 
-    /// <summary>Creates a new RunState object.</summary>
-    public RunState ()
+    /// <summary>Creates a new SessionToken object.</summary>
+    public SessionToken ()
     {
         Instances.Add (this);
     }

Terminal.Gui/App/SessionTokenEventArgs.cs

@@ -0,0 +1,12 @@
+namespace Terminal.Gui.App;
+
+/// <summary>Event arguments for events about <see cref="SessionToken"/></summary>
+public class SessionTokenEventArgs : EventArgs
+{
+    /// <summary>Creates a new instance of the <see cref="SessionTokenEventArgs"/> class</summary>
+    /// <param name="state"></param>
+    public SessionTokenEventArgs (SessionToken state) { State = state; }
+
+    /// <summary>The state being reported on by the event</summary>
+    public SessionToken State { get; }
+}

Terminal.Gui/App/Timeout/ITimedEvents.cs

@@ -23,22 +23,10 @@ public interface ITimedEvents
 
     /// <summary>
     ///     Invoked when a new timeout is added. To be used in the case when
-    ///     <see cref="Application.EndAfterFirstIteration"/> is <see langword="true"/>.
+    ///     <see cref="IApplication.StopAfterFirstIteration"/> is <see langword="true"/>.
     /// </summary>
     event EventHandler<TimeoutEventArgs>? Added;
 
-    /// <summary>
-    ///     Called from <see cref="IMainLoopDriver.EventsPending"/> to check if there are any outstanding timer handlers.
-    /// </summary>
-    /// <param name="waitTimeout">
-    ///     Returns the number of milliseconds remaining in the current timer (if any). Will be -1 if
-    ///     there are no active timers.
-    /// </param>
-    /// <returns>
-    ///     <see langword="true"/> if there is a timer active; otherwise, <see langword="false"/>.
-    /// </returns>
-    bool CheckTimers (out int waitTimeout);
-
     /// <summary>
     ///     Removes a previously scheduled timeout.
     /// </summary>

Terminal.Gui/Drawing/Cell.cs

@@ -5,7 +5,7 @@ namespace Terminal.Gui.Drawing;
 
 /// <summary>
 ///     Represents a single row/column in a Terminal.Gui rendering surface (e.g. <see cref="LineCanvas"/> and
-///     <see cref="IConsoleDriver"/>).
+///     <see cref="IDriver"/>).
 /// </summary>
 public record struct Cell (Attribute? Attribute = null, bool IsDirty = false, Rune Rune = default)
 {

Terminal.Gui/Drawing/Glyphs.cs

@@ -57,11 +57,11 @@ public class Glyphs
     [ConfigurationProperty (Scope = typeof (ThemeScope))]
     public static Rune CheckStateNone { get; set; } = (Rune)'□'; // TODO: Verify this works as broadly as possible
 
-    /// <summary>Selected indicator  (e.g. for <see cref="ListView"/> and <see cref="RadioGroup"/>).</summary>
+    /// <summary>Selected indicator  (e.g. for <see cref="ListView"/> and <see cref="OptionSelector"/>).</summary>
     [ConfigurationProperty (Scope = typeof (ThemeScope))]
     public static Rune Selected { get; set; } = (Rune)'◉';
 
-    /// <summary>Not Selected indicator (e.g. for <see cref="ListView"/> and <see cref="RadioGroup"/>).</summary>
+    /// <summary>Not Selected indicator (e.g. for <see cref="ListView"/> and <see cref="OptionSelector"/>).</summary>
     [ConfigurationProperty (Scope = typeof (ThemeScope))]
     public static Rune UnSelected { get; set; } = (Rune)'○';
 

Terminal.Gui/Drawing/LineCanvas/LineCanvas.cs

@@ -402,7 +402,7 @@ public class LineCanvas : IDisposable
         // TODO: Add other resolvers
     };
 
-    private Cell? GetCellForIntersects (IConsoleDriver? driver, ReadOnlySpan<IntersectionDefinition> intersects)
+    private Cell? GetCellForIntersects (IDriver? driver, ReadOnlySpan<IntersectionDefinition> intersects)
     {
         if (intersects.IsEmpty)
         {
@@ -422,7 +422,7 @@ public class LineCanvas : IDisposable
         return cell;
     }
 
-    private Rune? GetRuneForIntersects (IConsoleDriver? driver, ReadOnlySpan<IntersectionDefinition> intersects)
+    private Rune? GetRuneForIntersects (IDriver? driver, ReadOnlySpan<IntersectionDefinition> intersects)
     {
         if (intersects.IsEmpty)
         {
@@ -769,7 +769,7 @@ public class LineCanvas : IDisposable
         internal Rune _thickV;
         protected IntersectionRuneResolver () { SetGlyphs (); }
 
-        public Rune? GetRuneForIntersects (IConsoleDriver? driver, ReadOnlySpan<IntersectionDefinition> intersects)
+        public Rune? GetRuneForIntersects (IDriver? driver, ReadOnlySpan<IntersectionDefinition> intersects)
         {
             // Note that there aren't any glyphs for intersections of double lines with heavy lines
 

Terminal.Gui/Drawing/Ruler.cs

@@ -23,7 +23,8 @@ internal class Ruler
     /// <summary>Draws the <see cref="Ruler"/>.</summary>
     /// <param name="location">The location to start drawing the ruler, in screen-relative coordinates.</param>
     /// <param name="start">The start value of the ruler.</param>
-    public void Draw (Point location, int start = 0)
+    /// <param name="driver">Optional Driver. If not provided, driver will be used.</param>
+    public void Draw (Point location, int start = 0, IDriver? driver = null)
     {
         if (start < 0)
         {
@@ -35,14 +36,16 @@ internal class Ruler
             return;
         }
 
+        driver ??= driver;
+
         if (Orientation == Orientation.Horizontal)
         {
             string hrule =
                 _hTemplate.Repeat ((int)Math.Ceiling (Length + 2 / (double)_hTemplate.Length))! [start..(Length + start)];
 
             // Top
-            Application.Driver?.Move (location.X, location.Y);
-            Application.Driver?.AddStr (hrule);
+            driver?.Move (location.X, location.Y);
+            driver?.AddStr (hrule);
         }
         else
         {
@@ -52,8 +55,8 @@ internal class Ruler
 
             for (int r = location.Y; r < location.Y + Length; r++)
             {
-                Application.Driver?.Move (location.X, r);
-                Application.Driver?.AddRune ((Rune)vrule [r - location.Y]);
+                driver?.Move (location.X, r);
+                driver?.AddRune ((Rune)vrule [r - location.Y]);
             }
         }
     }

Terminal.Gui/Drawing/Sixel/SixelSupportDetector.cs

@@ -53,21 +53,21 @@ public class SixelSupportDetector
 
     private void TryComputeResolution (SixelSupportResult result, Action<SixelSupportResult> resultCallback)
     {
-        string windowSize;
+        string consoleSize;
         string sizeInChars;
 
         QueueRequest (
                       EscSeqUtils.CSI_RequestWindowSizeInPixels,
                       r1 =>
                       {
-                          windowSize = r1;
+                          consoleSize = r1;
 
                           QueueRequest (
-                                        EscSeqUtils.CSI_ReportTerminalSizeInChars,
+                                        EscSeqUtils.CSI_ReportWindowSizeInChars,
                                         r2 =>
                                         {
                                             sizeInChars = r2;
-                                            ComputeResolution (result, windowSize, sizeInChars);
+                                            ComputeResolution (result, consoleSize, sizeInChars);
                                             resultCallback (result);
                                         },
                                         () => resultCallback (result));
@@ -75,11 +75,11 @@ public class SixelSupportDetector
                       () => resultCallback (result));
     }
 
-    private void ComputeResolution (SixelSupportResult result, string windowSize, string sizeInChars)
+    private void ComputeResolution (SixelSupportResult result, string consoleSize, string sizeInChars)
     {
         // Fallback to window size in pixels and characters
         // Example [4;600;1200t
-        Match pixelMatch = Regex.Match (windowSize, @"\[\d+;(\d+);(\d+)t$");
+        Match pixelMatch = Regex.Match (consoleSize, @"\[\d+;(\d+);(\d+)t$");
 
         // Example [8;30;120t
         Match charMatch = Regex.Match (sizeInChars, @"\[\d+;(\d+);(\d+)t$");

Terminal.Gui/Drawing/Sixel/SixelToRender.cs

@@ -2,7 +2,7 @@
 
 /// <summary>
 ///     Describes a request to render a given <see cref="SixelData"/> at a given <see cref="ScreenPosition"/>.
-///     Requires that the terminal and <see cref="IConsoleDriver"/> both support sixel.
+///     Requires that the terminal and <see cref="IDriver"/> both support sixel.
 /// </summary>
 public class SixelToRender
 {

Terminal.Gui/Drawing/Thickness.cs

@@ -88,14 +88,17 @@ public record struct Thickness
     /// <param name="rect">The location and size of the rectangle that bounds the thickness rectangle, in screen coordinates.</param>
     /// <param name="diagnosticFlags"></param>
     /// <param name="label">The diagnostics label to draw on the bottom of the <see cref="Bottom"/>.</param>
+    /// <param name="driver">Optional driver. If not specified, <see cref="Application.Driver"/> will be used.</param>
     /// <returns>The inner rectangle remaining to be drawn.</returns>
-    public Rectangle Draw (Rectangle rect, ViewDiagnosticFlags diagnosticFlags = ViewDiagnosticFlags.Off, string? label = null)
+    public Rectangle Draw (Rectangle rect, ViewDiagnosticFlags diagnosticFlags = ViewDiagnosticFlags.Off, string? label = null, IDriver? driver = null)
     {
         if (rect.Size.Width < 1 || rect.Size.Height < 1)
         {
             return Rectangle.Empty;
         }
 
+        driver ??= Application.Driver;
+
         var clearChar = (Rune)' ';
         Rune leftChar = clearChar;
         Rune rightChar = clearChar;
@@ -118,71 +121,71 @@ public record struct Thickness
         // Draw the Top side
         if (Top > 0)
         {
-            Application.Driver?.FillRect (rect with { Height = Math.Min (rect.Height, Top) }, topChar);
+            driver?.FillRect (rect with { Height = Math.Min (rect.Height, Top) }, topChar);
         }
 
         // Draw the Left side
         // Draw the Left side
         if (Left > 0)
         {
-            Application.Driver?.FillRect (rect with { Width = Math.Min (rect.Width, Left) }, leftChar);
+            driver?.FillRect (rect with { Width = Math.Min (rect.Width, Left) }, leftChar);
         }
 
         // Draw the Right side
         if (Right > 0)
         {
-            Application.Driver?.FillRect (
-                                          rect with
-                                          {
-                                              X = Math.Max (0, rect.X + rect.Width - Right),
-                                              Width = Math.Min (rect.Width, Right)
-                                          },
-                                          rightChar
-                                         );
+            driver?.FillRect (
+                              rect with
+                              {
+                                  X = Math.Max (0, rect.X + rect.Width - Right),
+                                  Width = Math.Min (rect.Width, Right)
+                              },
+                              rightChar
+                             );
         }
 
         // Draw the Bottom side
         if (Bottom > 0)
         {
-            Application.Driver?.FillRect (
-                                          rect with
-                                          {
-                                              Y = rect.Y + Math.Max (0, rect.Height - Bottom),
-                                              Height = Bottom
-                                          },
-                                          bottomChar
-                                         );
+            driver?.FillRect (
+                              rect with
+                              {
+                                  Y = rect.Y + Math.Max (0, rect.Height - Bottom),
+                                  Height = Bottom
+                              },
+                              bottomChar
+                             );
         }
 
         if (diagnosticFlags.HasFlag (ViewDiagnosticFlags.Ruler))
         {
             // PERF: This can almost certainly be simplified down to a single point offset and fewer calls to Draw
             // Top
-            var hruler = new Ruler { Length = rect.Width, Orientation = Orientation.Horizontal };
+            Ruler hRuler = new () { Length = rect.Width, Orientation = Orientation.Horizontal };
 
             if (Top > 0)
             {
-                hruler.Draw (rect.Location);
+                hRuler.Draw (rect.Location, driver: driver);
             }
 
             //Left
-            var vruler = new Ruler { Length = rect.Height - 2, Orientation = Orientation.Vertical };
+            Ruler vRuler = new () { Length = rect.Height - 2, Orientation = Orientation.Vertical };
 
             if (Left > 0)
             {
-                vruler.Draw (rect.Location with { Y = rect.Y + 1 }, 1);
+                vRuler.Draw (rect.Location with { Y = rect.Y + 1 }, 1, driver);
             }
 
             // Bottom
             if (Bottom > 0)
             {
-                hruler.Draw (rect.Location with { Y = rect.Y + rect.Height - 1 });
+                hRuler.Draw (rect.Location with { Y = rect.Y + rect.Height - 1 }, driver: driver);
             }
 
             // Right
             if (Right > 0)
             {
-                vruler.Draw (new (rect.X + rect.Width - 1, rect.Y + 1), 1);
+                vRuler.Draw (new (rect.X + rect.Width - 1, rect.Y + 1), 1, driver);
             }
         }
 
@@ -191,7 +194,7 @@ public record struct Thickness
             // Draw the diagnostics label on the bottom
             string text = label is null ? string.Empty : $"{label} {this}";
 
-            var tf = new TextFormatter
+            TextFormatter tf = new ()
             {
                 Text = text,
                 Alignment = Alignment.Center,
@@ -200,9 +203,9 @@ public record struct Thickness
                 ConstrainToHeight = 1
             };
 
-            if (Application.Driver?.CurrentAttribute is { })
+            if (driver?.CurrentAttribute is { })
             {
-                tf.Draw (rect, Application.Driver!.CurrentAttribute, Application.Driver!.CurrentAttribute, rect);
+                tf.Draw (rect, driver!.CurrentAttribute, driver!.CurrentAttribute, rect, driver);
             }
         }
 
@@ -242,7 +245,7 @@ public record struct Thickness
     /// <returns></returns>
     public Region AsRegion (Rectangle rect)
     {
-        Region region = new Region (rect);
+        var region = new Region (rect);
         region.Exclude (GetInside (rect));
 
         return region;

Terminal.Gui/Drivers/AnsiHandling/AnsiEscapeSequenceRequest.cs

@@ -22,7 +22,7 @@ public class AnsiEscapeSequenceRequest : AnsiEscapeSequence
 
 
     /// <summary>
-    ///     Sends the <see cref="AnsiEscapeSequence.Request"/> to the raw output stream of the current <see cref="ConsoleDriver"/>.
+    ///     Sends the <see cref="AnsiEscapeSequence.Request"/> to the raw output stream of the current <see cref="IDriver"/>.
     ///     Only call this method from the main UI thread. You should use <see cref="AnsiRequestScheduler"/> if
     ///     sending many requests.
     /// </summary>