Fixes #4425 - `ApplicationImpl` internal (#4426)

* Pulled from v2_release

* Refactor migration guide for Terminal.Gui v2

Restructured and expanded the migration guide to provide a comprehensive resource for transitioning from Terminal.Gui v1 to v2. Key updates include:

- Added a Table of Contents for easier navigation.
- Summarized major architectural changes in v2, including the instance-based application model, IRunnable architecture, and 24-bit TrueColor support.
- Updated examples to reflect new patterns, such as initializers replacing constructors and explicit disposal using `IDisposable`.
- Documented changes to the layout system, including the removal of `Absolute`/`Computed` styles and the introduction of `Viewport`.
- Standardized event patterns to use `object sender, EventArgs args`.
- Detailed updates to the Keyboard, Mouse, and Navigation APIs, including configurable key bindings and viewport-relative mouse coordinates.
- Replaced legacy components like `ScrollView` and `ContextMenu` with built-in scrolling and `PopoverMenu`.
- Clarified disposal rules and introduced best practices for resource management.
- Provided a complete migration example and a summary of breaking changes.

This update aims to simplify the migration process by addressing breaking changes, introducing new features, and aligning with modern .NET conventions.

* Refactor to use Application.Instance for lifecycle management

Replaced all occurrences of `ApplicationImpl.Instance` with the new `Application.Instance` property across the codebase to align with the updated application lifecycle model.

Encapsulated the `ApplicationImpl` class by making it `internal`, ensuring it is no longer directly accessible outside its assembly. Introduced the `[Obsolete]` `Application.Instance` property as a backward-compatible singleton for the legacy static `Application` model, while encouraging the use of `Application.Create()` for new code.

Updated `MessageBox` methods to use `Application.Instance` for consistent modal dialog management. Improved documentation to reflect these changes and emphasize the transition to the instance-based application model.

Performed code cleanup in multiple classes to ensure consistency and maintainability. These changes maintain backward compatibility while preparing the codebase for the eventual removal of the legacy `ApplicationImpl` class.

* Fix doc bug

* - Removed obsolete `.cd` class diagram files.
- Introduced `IRunnable` interface for decoupling component execution.
- Added fluent API for running dialogs and retrieving results.
- Enhanced `View` with `App` and `Driver` properties for better decoupling.
- Improved testability with support for mock and real applications.
- Implemented `IDisposable` for proper resource cleanup.
- Replaced `RunnableSessionStack` with `SessionStack` for session management.
- Updated driver architecture to align with the new model.
- Scoped `IKeyboard` to application contexts for modularity.
- Updated documentation with migration strategies and best practices.

These changes modernize the library, improve maintainability, and align with current development practices.

Examples/UICatalog/Scenarios/ContextMenus.cs

@@ -49,7 +49,7 @@ public class ContextMenus : Scenario
             var text = "Context Menu";
             var width = 20;
 
-            CreateWinContextMenu (ApplicationImpl.Instance);
+            CreateWinContextMenu (Application.Instance);
 
             var label = new Label
             {

Examples/UICatalog/Scenarios/CsvEditor.cs

@@ -215,7 +215,7 @@ public class CsvEditor : Scenario
                                       _tableView.Table.Columns
                                      );
 
-            int? result = MessageBox.Query (ApplicationImpl.Instance,
+            int? result = MessageBox.Query (Application.Instance,
                                            "Column Type",
                                            "Pick a data type for the column",
                                            "Date",
@@ -308,7 +308,7 @@ public class CsvEditor : Scenario
 
         if (_tableView.SelectedColumn == -1)
         {
-            MessageBox.ErrorQuery (ApplicationImpl.Instance, "No Column", "No column selected", "Ok");
+            MessageBox.ErrorQuery (Application.Instance, "No Column", "No column selected", "Ok");
 
             return;
         }
@@ -320,7 +320,7 @@ public class CsvEditor : Scenario
         }
         catch (Exception ex)
         {
-            MessageBox.ErrorQuery (ApplicationImpl.Instance, "Could not remove column", ex.Message, "Ok");
+            MessageBox.ErrorQuery (Application.Instance, "Could not remove column", ex.Message, "Ok");
         }
     }
 
@@ -342,7 +342,7 @@ public class CsvEditor : Scenario
             }
             catch (Exception ex)
             {
-                MessageBox.ErrorQuery (ApplicationImpl.Instance, 60, 20, "Failed to set text", ex.Message, "Ok");
+                MessageBox.ErrorQuery (Application.Instance, 60, 20, "Failed to set text", ex.Message, "Ok");
             }
 
             _tableView.Update ();
@@ -388,7 +388,7 @@ public class CsvEditor : Scenario
 
         if (_tableView.SelectedColumn == -1)
         {
-            MessageBox.ErrorQuery (ApplicationImpl.Instance, "No Column", "No column selected", "Ok");
+            MessageBox.ErrorQuery (Application.Instance, "No Column", "No column selected", "Ok");
 
             return;
         }
@@ -413,7 +413,7 @@ public class CsvEditor : Scenario
         }
         catch (Exception ex)
         {
-            MessageBox.ErrorQuery (ApplicationImpl.Instance, "Error moving column", ex.Message, "Ok");
+            MessageBox.ErrorQuery (Application.Instance, "Error moving column", ex.Message, "Ok");
         }
     }
 
@@ -426,7 +426,7 @@ public class CsvEditor : Scenario
 
         if (_tableView.SelectedRow == -1)
         {
-            MessageBox.ErrorQuery (ApplicationImpl.Instance, "No Rows", "No row selected", "Ok");
+            MessageBox.ErrorQuery (Application.Instance, "No Rows", "No row selected", "Ok");
 
             return;
         }
@@ -462,7 +462,7 @@ public class CsvEditor : Scenario
         }
         catch (Exception ex)
         {
-            MessageBox.ErrorQuery (ApplicationImpl.Instance, "Error moving column", ex.Message, "Ok");
+            MessageBox.ErrorQuery (Application.Instance, "Error moving column", ex.Message, "Ok");
         }
     }
 
@@ -470,7 +470,7 @@ public class CsvEditor : Scenario
     {
         if (_tableView?.Table is null)
         {
-            MessageBox.ErrorQuery (ApplicationImpl.Instance, "No Table Loaded", "No table has currently be opened", "Ok");
+            MessageBox.ErrorQuery (Application.Instance, "No Table Loaded", "No table has currently be opened", "Ok");
 
             return true;
         }
@@ -582,7 +582,7 @@ public class CsvEditor : Scenario
         }
         catch (Exception ex)
         {
-            MessageBox.ErrorQuery (ApplicationImpl.Instance,
+            MessageBox.ErrorQuery (Application.Instance,
                                    "Open Failed",
                                    $"Error on line {lineNumber}{Environment.NewLine}{ex.Message}",
                                    "Ok"
@@ -612,7 +612,7 @@ public class CsvEditor : Scenario
     {
         if (_tableView?.Table is null || string.IsNullOrWhiteSpace (_currentFile) || _currentTable is null)
         {
-            MessageBox.ErrorQuery (ApplicationImpl.Instance, "No file loaded", "No file is currently loaded", "Ok");
+            MessageBox.ErrorQuery (Application.Instance, "No file loaded", "No file is currently loaded", "Ok");
 
             return;
         }
@@ -674,7 +674,7 @@ public class CsvEditor : Scenario
 
         if (col.DataType == typeof (string))
         {
-            MessageBox.ErrorQuery (ApplicationImpl.Instance,
+            MessageBox.ErrorQuery (Application.Instance,
                                    "Cannot Format Column",
                                    "String columns cannot be Formatted, try adding a new column to the table with a date/numerical Type",
                                    "Ok"
@@ -711,7 +711,7 @@ public class CsvEditor : Scenario
 
         if (_tableView.SelectedColumn == -1)
         {
-            MessageBox.ErrorQuery (ApplicationImpl.Instance, "No Column", "No column selected", "Ok");
+            MessageBox.ErrorQuery (Application.Instance, "No Column", "No column selected", "Ok");
 
             return;
         }

Examples/UICatalog/Scenarios/DynamicStatusBar.cs

@@ -79,7 +79,7 @@ public class DynamicStatusBar : Scenario
             }
             catch (Exception ex)
             {
-                MessageBox.ErrorQuery (ApplicationImpl.Instance, "Binding Error", $"Binding failed: {ex}.", "Ok");
+                MessageBox.ErrorQuery (Application.Instance, "Binding Error", $"Binding failed: {ex}.", "Ok");
             }
         }
     }
@@ -140,7 +140,7 @@ public class DynamicStatusBar : Scenario
         public TextView TextAction { get; }
         public TextField TextShortcut { get; }
         public TextField TextTitle { get; }
-        public Action CreateAction (DynamicStatusItem item) { return () => MessageBox.ErrorQuery (ApplicationImpl.Instance, item.Title, item.Action, "Ok"); }
+        public Action CreateAction (DynamicStatusItem item) { return () => MessageBox.ErrorQuery (Application.Instance, item.Title, item.Action, "Ok"); }
 
         public void EditStatusItem (Shortcut statusItem)
         {

Examples/UICatalog/Scenarios/Editor.cs

@@ -201,7 +201,7 @@ public class Editor : Scenario
         Debug.Assert (_textView.IsDirty);
 
         int? r = MessageBox.ErrorQuery (
-                                       ApplicationImpl.Instance,
+                                       Application.Instance,
                                        "Save File",
                                        $"Do you want save changes in {_appWindow.Title}?",
                                        "Yes",
@@ -236,7 +236,7 @@ public class Editor : Scenario
         }
         catch (Exception ex)
         {
-            MessageBox.ErrorQuery (ApplicationImpl.Instance, "Error", ex.Message, "Ok");
+            MessageBox.ErrorQuery (Application.Instance, "Error", ex.Message, "Ok");
         }
     }
 
@@ -315,11 +315,11 @@ public class Editor : Scenario
 
         if (!found)
         {
-            MessageBox.Query (ApplicationImpl.Instance, "Find", $"The following specified text was not found: '{_textToFind}'", "Ok");
+            MessageBox.Query (Application.Instance, "Find", $"The following specified text was not found: '{_textToFind}'", "Ok");
         }
         else if (gaveFullTurn)
         {
-            MessageBox.Query (ApplicationImpl.Instance,
+            MessageBox.Query (Application.Instance,
                               "Find",
                               $"No more occurrences were found for the following specified text: '{_textToFind}'",
                               "Ok"
@@ -895,7 +895,7 @@ public class Editor : Scenario
 
         if (_textView.ReplaceAllText (_textToFind, _matchCase, _matchWholeWord, _textToReplace))
         {
-            MessageBox.Query (ApplicationImpl.Instance,
+            MessageBox.Query (Application.Instance,
                               "Replace All",
                               $"All occurrences were replaced for the following specified text: '{_textToReplace}'",
                               "Ok"
@@ -903,7 +903,7 @@ public class Editor : Scenario
         }
         else
         {
-            MessageBox.Query (ApplicationImpl.Instance,
+            MessageBox.Query (Application.Instance,
                               "Replace All",
                               $"None of the following specified text was found: '{_textToFind}'",
                               "Ok"
@@ -1155,7 +1155,7 @@ public class Editor : Scenario
         {
             if (File.Exists (path))
             {
-                if (MessageBox.Query (ApplicationImpl.Instance,
+                if (MessageBox.Query (Application.Instance,
                                       "Save File",
                                       "File already exists. Overwrite any way?",
                                       "No",
@@ -1194,11 +1194,11 @@ public class Editor : Scenario
             _originalText = Encoding.Unicode.GetBytes (_textView.Text);
             _saved = true;
             _textView.ClearHistoryChanges ();
-            MessageBox.Query (ApplicationImpl.Instance, "Save File", "File was successfully saved.", "Ok");
+            MessageBox.Query (Application.Instance, "Save File", "File was successfully saved.", "Ok");
         }
         catch (Exception ex)
         {
-            MessageBox.ErrorQuery (ApplicationImpl.Instance, "Error", ex.Message, "Ok");
+            MessageBox.ErrorQuery (Application.Instance, "Error", ex.Message, "Ok");
 
             return false;
         }

Examples/UICatalog/Scenarios/FileDialogExamples.cs

@@ -133,7 +133,7 @@ public class FileDialogExamples : Scenario
                              }
                              catch (Exception ex)
                              {
-                                 MessageBox.ErrorQuery (ApplicationImpl.Instance, "Error", ex.ToString (), "_Ok");
+                                 MessageBox.ErrorQuery (Application.Instance, "Error", ex.ToString (), "_Ok");
                              }
                              finally
                              {
@@ -153,7 +153,7 @@ public class FileDialogExamples : Scenario
         {
             if (File.Exists (e.Dialog.Path))
             {
-                int? result = MessageBox.Query (ApplicationImpl.Instance, "Overwrite?", "File already exists", "_Yes", "_No");
+                int? result = MessageBox.Query (Application.Instance, "Overwrite?", "File already exists", "_Yes", "_No");
                 e.Cancel = result == 1;
             }
         }
@@ -248,7 +248,7 @@ public class FileDialogExamples : Scenario
 
             if (canceled)
             {
-                MessageBox.Query (ApplicationImpl.Instance,
+                MessageBox.Query (Application.Instance,
                                   "Canceled",
                                   "You canceled navigation and did not pick anything",
                                   "Ok"
@@ -256,7 +256,7 @@ public class FileDialogExamples : Scenario
             }
             else if (_cbAllowMultipleSelection.CheckedState == CheckState.Checked)
             {
-                MessageBox.Query (ApplicationImpl.Instance,
+                MessageBox.Query (Application.Instance,
                                   "Chosen!",
                                   "You chose:" + Environment.NewLine + string.Join (Environment.NewLine, multiSelected.Select (m => m)),
                                   "Ok"
@@ -264,7 +264,7 @@ public class FileDialogExamples : Scenario
             }
             else
             {
-                MessageBox.Query (ApplicationImpl.Instance,
+                MessageBox.Query (Application.Instance,
                                   "Chosen!",
                                   "You chose:" + Environment.NewLine + path,
                                   "Ok"

Examples/UICatalog/Scenarios/Generic.cs

@@ -29,7 +29,7 @@ public sealed class Generic : Scenario
                             {
                                 // When Accepting is handled, set e.Handled to true to prevent further processing.
                                 e.Handled = true;
-                                MessageBox.ErrorQuery (ApplicationImpl.Instance, "Error", "You pressed the button!", "_Ok");
+                                MessageBox.ErrorQuery (Application.Instance, "Error", "You pressed the button!", "_Ok");
                             };
 
         appWindow.Add (button);

Examples/UICatalog/Scenarios/HexEditor.cs

@@ -181,7 +181,7 @@ public class HexEditor : Scenario
         }
     }
 
-    private void Copy () { MessageBox.ErrorQuery (ApplicationImpl.Instance, "Not Implemented", "Functionality not yet implemented.", "Ok"); }
+    private void Copy () { MessageBox.ErrorQuery (Application.Instance, "Not Implemented", "Functionality not yet implemented.", "Ok"); }
 
     private void CreateDemoFile (string fileName)
     {
@@ -208,7 +208,7 @@ public class HexEditor : Scenario
         ms.Close ();
     }
 
-    private void Cut () { MessageBox.ErrorQuery (ApplicationImpl.Instance, "Not Implemented", "Functionality not yet implemented.", "Ok"); }
+    private void Cut () { MessageBox.ErrorQuery (Application.Instance, "Not Implemented", "Functionality not yet implemented.", "Ok"); }
 
     private Stream LoadFile ()
     {
@@ -216,7 +216,7 @@ public class HexEditor : Scenario
 
         if (!_saved && _hexView!.Edits.Count > 0 && _hexView.Source is {})
         {
-            if (MessageBox.ErrorQuery (ApplicationImpl.Instance,
+            if (MessageBox.ErrorQuery (Application.Instance,
                                        "Save",
                                        "The changes were not saved. Want to open without saving?",
                                        "_Yes",
@@ -267,7 +267,7 @@ public class HexEditor : Scenario
         d.Dispose ();
     }
 
-    private void Paste () { MessageBox.ErrorQuery (ApplicationImpl.Instance, "Not Implemented", "Functionality not yet implemented.", "_Ok"); }
+    private void Paste () { MessageBox.ErrorQuery (Application.Instance, "Not Implemented", "Functionality not yet implemented.", "_Ok"); }
     private void Quit () { Application.RequestStop (); }
 
     private void Save ()

Examples/UICatalog/Scenarios/Images.cs

@@ -183,7 +183,7 @@ public class Images : Scenario
 
         if (!_sixelSupportResult.SupportsTransparency)
         {
-            if (MessageBox.Query (ApplicationImpl.Instance,
+            if (MessageBox.Query (Application.Instance,
                                   "Transparency Not Supported",
                                   "It looks like your terminal does not support transparent sixel backgrounds. Do you want to try anyway?",
                                   "Yes",
@@ -288,7 +288,7 @@ public class Images : Scenario
         }
         catch (Exception ex)
         {
-            MessageBox.ErrorQuery (ApplicationImpl.Instance, "Could not open file", ex.Message, "Ok");
+            MessageBox.ErrorQuery (Application.Instance, "Could not open file", ex.Message, "Ok");
 
             return;
         }
@@ -492,7 +492,7 @@ public class Images : Scenario
     {
         if (_imageView.FullResImage == null)
         {
-            MessageBox.Query (ApplicationImpl.Instance, "No Image Loaded", "You must first open an image.  Use the 'Open Image' button above.", "Ok");
+            MessageBox.Query (Application.Instance, "No Image Loaded", "You must first open an image.  Use the 'Open Image' button above.", "Ok");
 
             return;
         }

Examples/UICatalog/Scenarios/InteractiveTree.cs

@@ -173,7 +173,7 @@ public class InteractiveTree : Scenario
 
                 if (parent is null)
                 {
-                    MessageBox.ErrorQuery (ApplicationImpl.Instance,
+                    MessageBox.ErrorQuery (Application.Instance,
                                            "Could not delete",
                                            $"Parent of '{toDelete}' was unexpectedly null",
                                            "Ok"

Examples/UICatalog/Scenarios/KeyBindings.cs

@@ -164,17 +164,17 @@ public class KeyBindingsDemo : View
 
         AddCommand (Command.Save, ctx =>
                                  {
-                                     MessageBox.Query (ApplicationImpl.Instance, $"{ctx.Command}", $"Ctx: {ctx}", buttons: "Ok");
+                                     MessageBox.Query (Application.Instance, $"{ctx.Command}", $"Ctx: {ctx}", buttons: "Ok");
                                      return true;
                                  });
         AddCommand (Command.New, ctx =>
                                 {
-                                    MessageBox.Query (ApplicationImpl.Instance, $"{ctx.Command}", $"Ctx: {ctx}", buttons: "Ok");
+                                    MessageBox.Query (Application.Instance, $"{ctx.Command}", $"Ctx: {ctx}", buttons: "Ok");
                                     return true;
                                 });
         AddCommand (Command.HotKey, ctx =>
         {
-            MessageBox.Query (ApplicationImpl.Instance, $"{ctx.Command}", $"Ctx: {ctx}\nCommand: {ctx.Command}", buttons: "Ok");
+            MessageBox.Query (Application.Instance, $"{ctx.Command}", $"Ctx: {ctx}\nCommand: {ctx.Command}", buttons: "Ok");
             SetFocus ();
             return true;
         });
@@ -189,7 +189,7 @@ public class KeyBindingsDemo : View
                                              {
                                                  return false;
                                              }
-                                             MessageBox.Query (ApplicationImpl.Instance, $"{keyCommandContext.Binding}", $"Key: {keyCommandContext.Binding.Key}\nCommand: {ctx.Command}", buttons: "Ok");
+                                             MessageBox.Query (Application.Instance, $"{keyCommandContext.Binding}", $"Key: {keyCommandContext.Binding.Key}\nCommand: {ctx.Command}", buttons: "Ok");
                                              Application.RequestStop ();
                                              return true;
                                          });

Examples/UICatalog/Scenarios/ListColumns.cs

@@ -336,7 +336,7 @@ public class ListColumns : Scenario
             }
             catch (Exception ex)
             {
-                MessageBox.ErrorQuery (ApplicationImpl.Instance, 60, 20, "Failed to set", ex.Message, "Ok");
+                MessageBox.ErrorQuery (Application.Instance, 60, 20, "Failed to set", ex.Message, "Ok");
             }
         }
     }

Examples/UICatalog/Scenarios/MessageBoxes.cs

@@ -251,7 +251,7 @@ public class MessageBoxes : Scenario
                                                {
                                                    buttonPressedLabel.Text =
                                                        $"{MessageBox.Query (
-                                                                            ApplicationImpl.Instance, width,
+                                                                            Application.Instance, width,
                                                                              height,
                                                                              titleEdit.Text,
                                                                              messageEdit.Text,
@@ -263,7 +263,7 @@ public class MessageBoxes : Scenario
                                                else
                                                {
                                                    buttonPressedLabel.Text =
-                                                       $"{MessageBox.ErrorQuery (ApplicationImpl.Instance,
+                                                       $"{MessageBox.ErrorQuery (Application.Instance,
                                                                                  width,
                                                                                  height,
                                                                                  titleEdit.Text,

Examples/UICatalog/Scenarios/MultiColouredTable.cs

@@ -99,7 +99,7 @@ public class MultiColouredTable : Scenario
             }
             catch (Exception ex)
             {
-                MessageBox.ErrorQuery (ApplicationImpl.Instance, 60, 20, "Failed to set text", ex.Message, "Ok");
+                MessageBox.ErrorQuery (Application.Instance, 60, 20, "Failed to set text", ex.Message, "Ok");
             }
 
             _tableView.Update ();

Examples/UICatalog/Scenarios/Navigation.cs

@@ -59,7 +59,7 @@ public class Navigation : Scenario
             Y = 0,
             Title = $"TopButton _{GetNextHotKey ()}"
         };
-        button.Accepting += (sender, args) => MessageBox.Query (ApplicationImpl.Instance, "hi", button.Title, "_Ok");
+        button.Accepting += (sender, args) => MessageBox.Query (Application.Instance, "hi", button.Title, "_Ok");
 
         testFrame.Add (button);
 

Examples/UICatalog/Scenarios/Notepad.cs

@@ -71,7 +71,7 @@ public class Notepad : Scenario
                                        new MenuItem
                                        {
                                            Title = "_About",
-                                           Action = () => MessageBox.Query (ApplicationImpl.Instance,  "Notepad", "About Notepad...", "Ok")
+                                           Action = () => MessageBox.Query (Application.Instance,  "Notepad", "About Notepad...", "Ok")
                                        }
                                    ]
                                   )
@@ -196,7 +196,7 @@ public class Notepad : Scenario
 
         if (tab.UnsavedChanges)
         {
-            int? result = MessageBox.Query (ApplicationImpl.Instance,
+            int? result = MessageBox.Query (Application.Instance,
                                             "Save Changes",
                                             $"Save changes to {tab.Text.TrimEnd ('*')}",
                                             "Yes",

Examples/UICatalog/Scenarios/RuneWidthGreaterThanOne.cs

@@ -166,7 +166,7 @@ public class RuneWidthGreaterThanOne : Scenario
     {
         if (_text is { })
         {
-            MessageBox.Query (ApplicationImpl.Instance, "Say Hello 你", $"Hello {_text.Text}", "Ok");
+            MessageBox.Query (Application.Instance, "Say Hello 你", $"Hello {_text.Text}", "Ok");
         }
     }
 
@@ -197,7 +197,7 @@ public class RuneWidthGreaterThanOne : Scenario
     {
         if (_text is { })
         {
-            MessageBox.Query (ApplicationImpl.Instance, "Say Hello", $"Hello {_text.Text}", "Ok");
+            MessageBox.Query (Application.Instance, "Say Hello", $"Hello {_text.Text}", "Ok");
         }
     }
 
@@ -252,7 +252,7 @@ public class RuneWidthGreaterThanOne : Scenario
     {
         if (_text is { })
         {
-            MessageBox.Query (ApplicationImpl.Instance, "こんにちはと言う", $"こんにちは {_text.Text}", "Ok");
+            MessageBox.Query (Application.Instance, "こんにちはと言う", $"こんにちは {_text.Text}", "Ok");
         }
     }
 

Examples/UICatalog/Scenarios/WindowsAndFrameViews.cs

@@ -18,7 +18,7 @@ public class WindowsAndFrameViews : Scenario
 
         static int? About ()
         {
-            return MessageBox.Query (ApplicationImpl.Instance,
+            return MessageBox.Query (Application.Instance,
                                      "About UI Catalog",
                                      "UI Catalog is a comprehensive sample library for Terminal.Gui",
                                      "Ok"

Examples/UICatalog/Scenarios/WizardAsView.cs

@@ -21,7 +21,7 @@ public class WizardAsView : Scenario
                                        {
                                            Title = "_Restart Configuration...",
                                            Action = () => MessageBox.Query (
-                                                                            ApplicationImpl.Instance,
+                                                                            Application.Instance,
                                                                             "Wizard",
                                                                             "Are you sure you want to reset the Wizard and start over?",
                                                                             "Ok",
@@ -32,7 +32,7 @@ public class WizardAsView : Scenario
                                        {
                                            Title = "Re_boot Server...",
                                            Action = () => MessageBox.Query (
-                                                                            ApplicationImpl.Instance,
+                                                                            Application.Instance,
                                                                             "Wizard",
                                                                             "Are you sure you want to reboot the server start over?",
                                                                             "Ok",
@@ -43,7 +43,7 @@ public class WizardAsView : Scenario
                                        {
                                            Title = "_Shutdown Server...",
                                            Action = () => MessageBox.Query (
-                                                                            ApplicationImpl.Instance,
+                                                                            Application.Instance,
                                                                             "Wizard",
                                                                             "Are you sure you want to cancel setup and shutdown?",
                                                                             "Ok",

Terminal.Gui/App/Application.Lifecycle.cs

@@ -10,6 +10,22 @@ namespace Terminal.Gui.App;
 
 public static partial class Application // Lifecycle (Init/Shutdown)
 {
+    /// <summary>
+    ///     Gets the singleton <see cref="IApplication"/> instance used by the legacy static Application model.
+    /// </summary>
+    /// <remarks>
+    ///     <para>
+    ///         For new code, prefer using <see cref="Create"/> to get an instance-based application.
+    ///         This property is provided for backward compatibility and internal use.
+    ///     </para>
+    ///     <para>
+    ///         This property returns the same singleton instance used by the legacy static <see cref="Application"/>
+    ///         methods like <see cref="Init"/> and <see cref="Run(IRunnable, Func{Exception, bool}?)"/>.
+    ///     </para>
+    /// </remarks>
+    [Obsolete ("The legacy static Application object is going away. Use Application.Create() for new code.")]
+    public static IApplication Instance => ApplicationImpl.Instance;
+
     /// <summary>
     ///     Creates a new <see cref="IApplication"/> instance.
     /// </summary>
@@ -49,7 +65,7 @@ public static partial class Application // Lifecycle (Init/Shutdown)
         internal set => ApplicationImpl.Instance.MainThreadId = value;
     }
 
-    /// <inheritdoc cref="IApplication.Dispose"/>
+    /// <inheritdoc cref="IDisposable.Dispose"/>
     [Obsolete ("The legacy static Application object is going away.")]
     public static void Shutdown () => ApplicationImpl.Instance.Dispose ();
 

Terminal.Gui/App/Application.cd

@@ -1,117 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<ClassDiagram MajorVersion="1" MinorVersion="1">
-  <Class Name="Terminal.Gui.App.Application">
-    <Position X="2.25" Y="1.5" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>gEK4FIgQOAQIuhQeBwoUgSCgAAJL0AACESIKoAiBWw8=</HashCode>
-      <FileName>App\Application.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Class Name="Terminal.Gui.App.ApplicationNavigation" Collapsed="true">
-    <Position X="14.75" Y="2.75" Width="2" />
-    <TypeIdentifier>
-      <HashCode>AABAAAAAAABCAAAAAAAAAAAAAAAAIgIAAAAAAAAAAAA=</HashCode>
-      <FileName>App\ApplicationNavigation.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Class Name="Terminal.Gui.App.IterationEventArgs" Collapsed="true">
-    <Position X="17" Y="3" Width="2" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=</HashCode>
-      <FileName>App\IterationEventArgs.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Class Name="Terminal.Gui.App.MainLoop" Collapsed="true" BaseTypeListCollapsed="true">
-    <Position X="11.25" Y="3.75" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAACAAAAAAAAAAAAAACBAAEAAIIAIAgAAAEAI=</HashCode>
-      <FileName>App\MainLoop.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" Collapsed="true" />
-  </Class>
-  <Class Name="Terminal.Gui.App.MainLoopSyncContext" Collapsed="true">
-    <Position X="13" Y="3.75" Width="2" />
-    <TypeIdentifier>
-      <HashCode>AAAAAgAAAAAAAAAAAEAAAAAACAAAAAAAAAAAAAAAAAA=</HashCode>
-      <FileName>App\MainLoopSyncContext.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <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\SessionToken.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" Collapsed="true" />
-  </Class>
-  <Class Name="Terminal.Gui.App.SessionTokenEventArgs" Collapsed="true">
-    <Position X="17" Y="4" Width="2" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAA=</HashCode>
-      <FileName>App\SessionTokenEventArgs.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Class Name="Terminal.Gui.App.Timeout" Collapsed="true">
-    <Position X="11.25" Y="4.75" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAIAQAA=</HashCode>
-      <FileName>App\Timeout.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Class Name="Terminal.Gui.App.TimeoutEventArgs" Collapsed="true">
-    <Position X="13" Y="4.75" Width="2" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAAAAAAAAAAAAAAAAAACAIAAAAAAAAAAAA=</HashCode>
-      <FileName>App\TimeoutEventArgs.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Class Name="Terminal.Gui.App.ApplicationImpl" BaseTypeListCollapsed="true">
-    <Position X="4" Y="5" Width="2" />
-    <TypeIdentifier>
-      <HashCode>AABgAAAAIAAIAgQUAAAAAQAAAAAAAAAAQAAKgAAAEAI=</HashCode>
-      <FileName>App\ApplicationImpl.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="Terminal.Gui.App.MouseGrabHandler" Collapsed="true">
-    <Position X="6.25" Y="9.25" Width="2" />
-    <TypeIdentifier>
-      <HashCode>BAAgAAAAgABAAoAAAAAAABAAACEAAAAAAABAAgAAAAA=</HashCode>
-      <FileName>App\MouseGrabHandler.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Interface Name="Terminal.Gui.App.IMainLoopDriver">
-    <Position X="11.25" Y="1.5" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAACAAAAAQAAAAABAAAAAAAEAAAAAAAAAAAAAA=</HashCode>
-      <FileName>App\MainLoop.cs</FileName>
-    </TypeIdentifier>
-  </Interface>
-  <Interface Name="Terminal.Gui.App.IApplication">
-    <Position X="4" Y="1.5" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AAAgAAAAAAAIAgQUAAAAAQAAAAAAAAAAAAAKgAAAEAI=</HashCode>
-      <FileName>App\IApplication.cs</FileName>
-    </TypeIdentifier>
-    <ShowAsAssociation>
-      <Property Name="MouseGrabHandler" />
-      <Property Name="TimedEvents" />
-    </ShowAsAssociation>
-  </Interface>
-  <Interface Name="Terminal.Gui.App.IMouseGrabHandler">
-    <Position X="7" Y="1.5" Width="2" />
-    <TypeIdentifier>
-      <HashCode>BAAgAAAAAAAAAgAAAAAAABAAACEAAAAAAAAAAgAAAAA=</HashCode>
-      <FileName>App\IMouseGrabHandler.cs</FileName>
-    </TypeIdentifier>
-  </Interface>
-  <Interface Name="Terminal.Gui.App.ITimedEvents">
-    <Position X="7" Y="4.5" Width="2" />
-    <TypeIdentifier>
-      <HashCode>BAAAIAAAAQAAAAAQACAAAIBAAQAAAAAAAAAIgAAAAAA=</HashCode>
-      <FileName>App\ITimedEvents.cs</FileName>
-    </TypeIdentifier>
-  </Interface>
-  <Font Name="Segoe UI" Size="9" />
-</ClassDiagram>

Terminal.Gui/App/ApplicationImpl.Driver.cs

@@ -2,7 +2,7 @@ using System.Collections.Concurrent;
 
 namespace Terminal.Gui.App;
 
-public partial class ApplicationImpl
+internal partial class ApplicationImpl
 {
     /// <inheritdoc/>
     public IDriver? Driver { get; set; }

Terminal.Gui/App/ApplicationImpl.Lifecycle.cs

@@ -3,7 +3,7 @@ using System.Diagnostics.CodeAnalysis;
 
 namespace Terminal.Gui.App;
 
-public partial class ApplicationImpl
+internal partial class ApplicationImpl
 {
     /// <inheritdoc/>
     public int? MainThreadId { get; set; }

Terminal.Gui/App/ApplicationImpl.Run.cs

@@ -3,7 +3,7 @@ using System.Diagnostics.CodeAnalysis;
 
 namespace Terminal.Gui.App;
 
-public partial class ApplicationImpl
+internal partial class ApplicationImpl
 {
     // Lock object to protect session stack operations and cached state updates
     private readonly object _sessionStackLock = new ();

Terminal.Gui/App/ApplicationImpl.Screen.cs

@@ -1,7 +1,7 @@
 
 namespace Terminal.Gui.App;
 
-public partial class ApplicationImpl
+internal partial class ApplicationImpl
 {
     /// <inheritdoc/>
     public event EventHandler<EventArgs<Rectangle>>? ScreenChanged;

Terminal.Gui/App/ApplicationImpl.cs

@@ -6,7 +6,7 @@ namespace Terminal.Gui.App;
 ///     Implementation of core <see cref="Application"/> methods using the modern
 ///     main loop architecture with component factories for different platforms.
 /// </summary>
-public partial class ApplicationImpl : IApplication
+internal partial class ApplicationImpl : IApplication
 {
     /// <summary>
     ///     INTERNAL: Creates a new instance of the Application backend and subscribes to Application configuration property
@@ -75,7 +75,7 @@ public partial class ApplicationImpl : IApplication
     /// <summary>
     ///     Gets the currently configured backend implementation of <see cref="Application"/> gateway methods.
     /// </summary>
-    public static IApplication Instance
+    internal static IApplication Instance
     {
         get
         {

Terminal.Gui/Views/Autocomplete/Autocomplete.cd

@@ -1,79 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<ClassDiagram MajorVersion="1" MinorVersion="1">
-  <Class Name="Terminal.Gui.Views.AppendAutocomplete" Collapsed="true">
-    <Position X="0.5" Y="6.5" Width="2" />
-    <TypeIdentifier>
-      <HashCode>AAAgAABAAQIAAAAAAAAAAAAABAAAIAQAgAEIAggAIAA=</HashCode>
-      <FileName>Core\Autocomplete\AppendAutocomplete.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Class Name="Terminal.Gui.Views.AutocompleteBase" Collapsed="true">
-    <Position X="1.75" Y="5.25" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AAQgAAAAAUAAIAAAAAIAAAAAAAEAIAQIgQAIQAAAMBA=</HashCode>
-      <FileName>Core\Autocomplete\AutocompleteBase.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="Terminal.Gui.Views.PopupAutocomplete" Collapsed="true">
-    <Position X="2.75" Y="6.5" Width="1.5" />
-    <NestedTypes>
-      <Class Name="Terminal.Gui.Views.PopupAutocomplete.Popup" Collapsed="true">
-        <TypeIdentifier>
-          <NewMemberFileName>Core\Autocomplete\PopupAutocomplete.cs</NewMemberFileName>
-        </TypeIdentifier>
-      </Class>
-    </NestedTypes>
-    <TypeIdentifier>
-      <HashCode>IAEhAAQAASBEQAAAAAIBAAgYAAAAIAwAwKAAQACBAAA=</HashCode>
-      <FileName>Core\Autocomplete\PopupAutocomplete.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Class Name="Terminal.Gui.Views.SingleWordSuggestionGenerator" BaseTypeListCollapsed="true">
-    <Position X="6.25" Y="3.5" Width="3" />
-    <TypeIdentifier>
-      <HashCode>CEAAAAAAAAAAAAAAAAAAAAAAAAIAAAAAAAAAAAAAIAA=</HashCode>
-      <FileName>Core\Autocomplete\SingleWordSuggestionGenerator.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="Terminal.Gui.Views.Suggestion">
-    <Position X="4.5" Y="2.5" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAAAEAAAAAABAAAAAAAAAAAAAAAAAAAAAE=</HashCode>
-      <FileName>Core\Autocomplete\Suggestion.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Class Name="Terminal.Gui.Views.TextFieldAutocomplete" Collapsed="true">
-    <Position X="1.5" Y="7.5" Width="2" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAAAAAAAAAAAAAIAAAAAAAAgAAAAAAAAAA=</HashCode>
-      <FileName>Views\TextField.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Class Name="Terminal.Gui.Views.TextViewAutocomplete" Collapsed="true">
-    <Position X="3.75" Y="7.5" Width="2.25" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAAAAAAAAAAAAAIAAAAAAAAgAAAAAAAAAA=</HashCode>
-      <FileName>Views\TextView.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Interface Name="Terminal.Gui.Views.IAutocomplete">
-    <Position X="1.75" Y="0.5" Width="2.5" />
-    <TypeIdentifier>
-      <HashCode>AAQgAAAAAUAAIAAAAAAAAAAAAAEAIAQIgQAIQAAAMBA=</HashCode>
-      <FileName>Core\Autocomplete\IAutocomplete.cs</FileName>
-    </TypeIdentifier>
-    <ShowAsAssociation>
-      <Property Name="SuggestionGenerator" />
-    </ShowAsAssociation>
-  </Interface>
-  <Interface Name="Terminal.Gui.Views.ISuggestionGenerator">
-    <Position X="6.25" Y="1.75" Width="2.25" />
-    <TypeIdentifier>
-      <HashCode>AEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAIAA=</HashCode>
-      <FileName>Core\Autocomplete\ISuggestionGenerator.cs</FileName>
-    </TypeIdentifier>
-  </Interface>
-  <Font Name="Segoe UI" Size="9" />
-</ClassDiagram>

Terminal.Gui/Views/CollectionNavigation/CollectionNavigation.cd

@@ -1,124 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<ClassDiagram MajorVersion="1" MinorVersion="1">
-  <Comment CommentText="Views that use the CollectionNavigation system">
-    <Position X="0.5" Y="0.5" Height="0.458" Width="1.856" />
-  </Comment>
-  <Comment CommentText="Specialized navigators for each collection type (e.g. list, tree etc)">
-    <Position X="4.646" Y="0.5" Height="0.5" Width="3.169" />
-  </Comment>
-  <Comment CommentText="Shared matching component (users should provide alternative implementations of this class if they want to modify collection navigation behaviour)">
-    <Position X="9.448" Y="0.5" Height="0.708" Width="3.169" />
-  </Comment>
-  <Class Name="Terminal.Gui.Views.CollectionNavigatorBase" Collapsed="true">
-    <Position X="6.25" Y="1.5" Width="2" />
-    <TypeIdentifier>
-      <HashCode>AAgEAAAAAAAQAAAIAAEAAgAAAAAABAAEAAAAACwAAAA=</HashCode>
-      <FileName>Views\CollectionNavigation\CollectionNavigatorBase.cs</FileName>
-    </TypeIdentifier>
-    <ShowAsAssociation>
-      <Property Name="Matcher" />
-    </ShowAsAssociation>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="Terminal.Gui.Views.CollectionNavigator" Collapsed="true">
-    <Position X="4.5" Y="3.5" Width="2" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAAQAAAAAAAAgAAAAAAAAAEAAAAAAAAAAA=</HashCode>
-      <FileName>Views\CollectionNavigation\CollectionNavigator.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="Terminal.Gui.Views.DefaultCollectionNavigatorMatcher">
-    <Position X="9.5" Y="2.5" Width="2.75" />
-    <TypeIdentifier>
-      <HashCode>AAACAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAQA=</HashCode>
-      <FileName>Views\CollectionNavigation\DefaultCollectionNavigatorMatcher.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="Terminal.Gui.Views.TableCollectionNavigator" Collapsed="true">
-    <Position X="4.75" Y="6.5" Width="2.25" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAAAAAAAAAAAgAAAAAAAAAEAAAAIAAAAAA=</HashCode>
-      <FileName>Views\CollectionNavigation\TableCollectionNavigator.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Class Name="Terminal.Gui.Views.ListView" Collapsed="true">
-    <Position X="0.5" Y="4.25" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AAE+ASAkEnAAABAAKGAggYAZJAIAABEAcBAaAwAQIAA=</HashCode>
-      <FileName>Views\ListView.cs</FileName>
-    </TypeIdentifier>
-    <ShowAsAssociation>
-      <Property Name="KeystrokeNavigator" />
-    </ShowAsAssociation>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="Terminal.Gui.Views.TableView" Collapsed="true" BaseTypeListCollapsed="true">
-    <Position X="0.5" Y="6.5" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>QwUeAxwgICIAcABIABeR0oBAkhoFGGOBDABgAN3oPEI=</HashCode>
-      <FileName>Views\TableView\TableView.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="Terminal.Gui.Views.TreeView" Collapsed="true">
-    <Position X="0.5" Y="3" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAA=</HashCode>
-      <FileName>Views\TreeView\TreeView.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="Terminal.Gui.Views.TreeView&lt;T&gt;" Collapsed="true">
-    <Position X="0.5" Y="2" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>UwAGySBgBSBGMAQgIiCaBDUItJIBSAWwRMQOSgQCwJI=</HashCode>
-      <FileName>Views\TreeView\TreeView.cs</FileName>
-    </TypeIdentifier>
-    <ShowAsAssociation>
-      <Property Name="KeystrokeNavigator" />
-    </ShowAsAssociation>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="Terminal.Gui.Views.FileDialog" Collapsed="true">
-    <Position X="0.5" Y="5.5" Width="1.75" />
-    <Compartments>
-      <Compartment Name="Nested Types" Collapsed="false" />
-    </Compartments>
-    <TypeIdentifier>
-      <HashCode>iIY4LQFUHDKVIHIESBoigQcFT6GxhBDABGJItBQAwAQ=</HashCode>
-      <FileName>Views\FileDialogs\FileDialog.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="Terminal.Gui.Views.FileDialogCollectionNavigator" Collapsed="true">
-    <Position X="4.75" Y="5.5" Width="2.25" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAAAAAAAAAAAgAAAAAAAAAEAAAAAAAAAAA=</HashCode>
-      <FileName>Views\FileDialogs\FileDialogCollectionNavigator.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Interface Name="Terminal.Gui.Views.ICollectionNavigatorMatcher" Collapsed="true">
-    <Position X="9.5" Y="1.5" Width="2.75" />
-    <TypeIdentifier>
-      <HashCode>AAACAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAA=</HashCode>
-      <FileName>Views\CollectionNavigation\ICollectionNavigatorMatcher.cs</FileName>
-    </TypeIdentifier>
-  </Interface>
-  <Interface Name="Terminal.Gui.Views.IListCollectionNavigator" Collapsed="true">
-    <Position X="3.75" Y="2.25" Width="2" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=</HashCode>
-      <FileName>Views\CollectionNavigation\IListCollectionNavigator.cs</FileName>
-    </TypeIdentifier>
-  </Interface>
-  <Interface Name="Terminal.Gui.Views.ICollectionNavigator" Collapsed="true">
-    <Position X="3.75" Y="1.5" Width="2" />
-    <TypeIdentifier>
-      <HashCode>AAgAAAAAAAAAAAAIAAAAAAAAAAAABAAAAAAAACgAAAA=</HashCode>
-      <FileName>Views\CollectionNavigation\ICollectionNavigator.cs</FileName>
-    </TypeIdentifier>
-  </Interface>
-  <Font Name="Segoe UI" Size="9" />
-</ClassDiagram>

Terminal.Gui/Views/FileDialogs/FileDialog.cd

@@ -1,168 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<ClassDiagram MajorVersion="1" MinorVersion="1">
-  <Class Name="Terminal.Gui.FileServices.DefaultSearchMatcher" Collapsed="true" BaseTypeListCollapsed="true">
-    <Position X="9.25" Y="6" Width="2" />
-    <TypeIdentifier>
-      <HashCode>AAACAAAAAAgAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=</HashCode>
-      <FileName>FileServices\DefaultSearchMatcher.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="Terminal.Gui.FileServices.FileSystemInfoStats">
-    <Position X="14" Y="0.5" Width="2.5" />
-    <TypeIdentifier>
-      <HashCode>ABAIQAIIIAAAAAACQAAAAIQAAAQAAIAAAQAAAAAIAAI=</HashCode>
-      <FileName>FileServices\FileSystemInfoStats.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Class Name="Terminal.Gui.Views.FileDialog">
-    <Position X="0.5" Y="0.5" Width="2.75" />
-    <Compartments>
-      <Compartment Name="Fields" Collapsed="true" />
-      <Compartment Name="Methods" Collapsed="true" />
-      <Compartment Name="Nested Types" Collapsed="false" />
-    </Compartments>
-    <NestedTypes>
-      <Class Name="Terminal.Gui.Views.FileDialog.SearchState" Collapsed="true">
-        <TypeIdentifier>
-          <NewMemberFileName>Views\FileDialogs\FileDialog.cs</NewMemberFileName>
-        </TypeIdentifier>
-      </Class>
-    </NestedTypes>
-    <TypeIdentifier>
-      <HashCode>iIY4LQFUHDKVIHIESBoigQcFT6GxhBDABGJItBQAwAQ=</HashCode>
-      <FileName>Views\FileDialogs\FileDialog.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="Terminal.Gui.Views.FileDialogStyle">
-    <Position X="3.5" Y="0.5" Width="2.75" />
-    <TypeIdentifier>
-      <HashCode>GgBAAAFHAAAAuAAAAAAAEAQQBYAAKREAAAAYQCCAAAA=</HashCode>
-      <FileName>Views\FileDialogs\FileDialogStyle.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Class Name="Terminal.Gui.Views.FilesSelectedEventArgs">
-    <Position X="6.5" Y="0.5" Width="2" />
-    <Compartments>
-      <Compartment Name="Methods" Collapsed="true" />
-    </Compartments>
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAEAAAAAAAAAA=</HashCode>
-      <FileName>Views\FileDialogs\FilesSelectedEventArgs.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Class Name="Terminal.Gui.Views.FileDialogHistory">
-    <Position X="9.25" Y="0.5" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AQABAgEAAAAAAAAAIACAAAAAAAAAAQAAAAAAAAAADAI=</HashCode>
-      <FileName>Views\FileDialogs\FileDialogHistory.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Class Name="Terminal.Gui.Views.FileDialogState">
-    <Position X="11.5" Y="0.5" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AABAABAAAAAAAAIAAAAEQAAAAAAAQAAAAgAAAAAAAAI=</HashCode>
-      <FileName>Views\FileDialogs\FileDialogState.cs</FileName>
-    </TypeIdentifier>
-    <ShowAsCollectionAssociation>
-      <Property Name="Children" />
-    </ShowAsCollectionAssociation>
-  </Class>
-  <Class Name="Terminal.Gui.Views.AllowedType" BaseTypeListCollapsed="true">
-    <Position X="13.25" Y="5.75" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAgAAAEAAAAAAAAAAAAAAAAAAgAAAAABAA=</HashCode>
-      <FileName>Views\FileDialogs\AllowedType.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="Terminal.Gui.Views.AllowedTypeAny" BaseTypeListCollapsed="true">
-    <Position X="11.75" Y="5.75" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAAAAAEAAAAAAAAAAAAAAAAAAAAAAAABAA=</HashCode>
-      <FileName>Views\FileDialogs\AllowedType.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="Terminal.Gui.Text.NerdFonts">
-    <Position X="9.25" Y="6.75" Width="2" />
-    <Compartments>
-      <Compartment Name="Fields" Collapsed="true" />
-    </Compartments>
-    <TypeIdentifier>
-      <HashCode>AIACAAABQAAAAAAAAAAACAAAIACAAAAAAAIAAAAAAAA=</HashCode>
-      <FileName>Text\NerdFonts.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Class Name="Terminal.Gui.FileServices.FileSystemTreeBuilder" BaseTypeListCollapsed="true">
-    <Position X="0.5" Y="6.75" Width="1.75" />
-    <TypeIdentifier>
-      <HashCode>EAAAAAAAAAAAAAAAAAAABAAwAAAAQAAAAABAAAAACAA=</HashCode>
-      <FileName>FileServices\FileSystemTreeBuilder.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="Terminal.Gui.Views.DefaultFileOperations" BaseTypeListCollapsed="true">
-    <Position X="7" Y="6" Width="2" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAAACAAAAAAACAAAAEAAAAAAAAAAAAAgAA=</HashCode>
-      <FileName>Views\FileDialogs\DefaultFileOperations.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="Terminal.Gui.FileServices.FileSystemColorProvider" Collapsed="true">
-    <Position X="7" Y="8.5" Width="2" />
-    <TypeIdentifier>
-      <HashCode>AgAAAAAAAEAAAAAAAAAAAAEAAAAAAACAAAAAAAAAAAA=</HashCode>
-      <FileName>FileServices\FileSystemColorProvider.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Class Name="Terminal.Gui.FileServices.FileSystemIconProvider" Collapsed="true">
-    <Position X="7" Y="7.75" Width="2" />
-    <TypeIdentifier>
-      <HashCode>ABAAAAAAAACAQAAAAAAAAEAgAAAAAQAAAAAAAAAAAiA=</HashCode>
-      <FileName>FileServices\FileSystemIconProvider.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Class Name="Terminal.Gui.Views.FileDialogTableSource">
-    <Position X="2.5" Y="8" Width="2.5" />
-    <Compartments>
-      <Compartment Name="Fields" Collapsed="true" />
-    </Compartments>
-    <TypeIdentifier>
-      <HashCode>AQAAAAAAIAACAEAACAAAAAACAAAEAAAEAAAAgAgBBAA=</HashCode>
-      <FileName>Views\FileDialogs\FileDialogTableSource.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Interface Name="Terminal.Gui.FileServices.IFileOperations">
-    <Position X="7" Y="4.25" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAAACAAAAAAAAAAAAEAAAAAAAAAAAAAgAA=</HashCode>
-      <FileName>FileServices\IFileOperations.cs</FileName>
-    </TypeIdentifier>
-  </Interface>
-  <Interface Name="Terminal.Gui.FileServices.ISearchMatcher">
-    <Position X="9.25" Y="4.25" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AAACAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=</HashCode>
-      <FileName>FileServices\ISearchMatcher.cs</FileName>
-    </TypeIdentifier>
-  </Interface>
-  <Interface Name="Terminal.Gui.Views.IAllowedType" Collapsed="true">
-    <Position X="12" Y="4.25" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAA=</HashCode>
-      <FileName>Views\FileDialogs\AllowedType.cs</FileName>
-    </TypeIdentifier>
-  </Interface>
-  <Enum Name="Terminal.Gui.Views.OpenMode">
-    <Position X="7.5" Y="2.5" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AAAAABAAAAAAACAAAAAAAAAAAAAEAAAAAAAAAAAAAAA=</HashCode>
-      <FileName>Views\FileDialogs\OpenMode.cs</FileName>
-    </TypeIdentifier>
-  </Enum>
-  <Font Name="Segoe UI" Size="9" />
-</ClassDiagram>

Terminal.Gui/Views/MessageBox.cs

@@ -18,7 +18,7 @@ namespace Terminal.Gui.Views;
 ///         <b>Important:</b> All MessageBox methods require an <see cref="IApplication"/> instance to be passed.
 ///         This enables proper modal dialog management and respects the application's lifecycle. Pass your
 ///         application instance (from <see cref="Application.Create()"/>) or use the legacy
-///         <see cref="ApplicationImpl.Instance"/> if using the static Application pattern.
+///         <see cref="Application.Instance"/> if using the static Application pattern.
 ///     </para>
 ///     <para>
 ///         Example using instance-based pattern:

Terminal.Gui/Views/Shortcut.cs

@@ -634,7 +634,7 @@ public class Shortcut : View, IOrientation, IDesignable
         get => _bindKeyToApplication;
         set
         {
-            App ??= SuperView?.App ?? ApplicationImpl.Instance; // HACK: Remove once legacy static Application is gone
+            App ??= SuperView?.App ?? Application.Instance; // HACK: Remove once legacy static Application is gone
             Debug.Assert (App is { });
 
             if (value == _bindKeyToApplication)

Tests/TerminalGuiFluentTesting/ClassDiagram1.cd

@@ -1,89 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<ClassDiagram MajorVersion="1" MinorVersion="1">
-  <Class Name="TerminalGuiFluentTesting.With" Collapsed="true">
-    <Position X="0.5" Y="1.5" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAIAAAAAIAAAAAA=</HashCode>
-      <FileName>With.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Class Name="TerminalGuiFluentTesting.FakeInput&lt;T&gt;" Collapsed="true">
-    <Position X="7" Y="1.5" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AQAAAAAAACAAAQEAAAAgAAAAAAAAAAAAAAAAAAAAAAI=</HashCode>
-      <FileName>FakeInput.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="TerminalGuiFluentTesting.FakeNetInput" Collapsed="true">
-    <Position X="8.25" Y="2.75" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=</HashCode>
-      <FileName>FakeNetInput.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="TerminalGuiFluentTesting.FakeWindowsInput" Collapsed="true">
-    <Position X="6" Y="2.75" Width="1.75" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=</HashCode>
-      <FileName>FakeWindowsInput.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="TerminalGuiFluentTesting.FakeOutput" Collapsed="true" BaseTypeListCollapsed="true">
-    <Position X="5.5" Y="0.5" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAgCAAgAAAAAAAAAAAAAAAQAAAMAAAAAEAAAA=</HashCode>
-      <FileName>FakeOutput.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="TerminalGuiFluentTesting.GuiTestContext" BaseTypeListCollapsed="true">
-    <Position X="2.25" Y="0.5" Width="2.25" />
-    <Compartments>
-      <Compartment Name="Fields" Collapsed="true" />
-    </Compartments>
-    <TypeIdentifier>
-      <HashCode>ABJAAAIAACBACRAAg4IAAAAgAJIEgQQAKACIBACAIgI=</HashCode>
-      <FileName>GuiTestContext.cs</FileName>
-    </TypeIdentifier>
-    <ShowAsAssociation>
-      <Field Name="_output" />
-      <Field Name="_winInput" />
-      <Field Name="_netInput" />
-    </ShowAsAssociation>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="TerminalGuiFluentTesting.TextWriterLoggerProvider" Collapsed="true">
-    <Position X="10" Y="2.75" Width="2" />
-    <TypeIdentifier>
-      <HashCode>AAAAAIAAACAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=</HashCode>
-      <FileName>TextWriterLoggerProvider.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="TerminalGuiFluentTesting.TextWriterLogger" Collapsed="true">
-    <Position X="10" Y="1.75" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAAAAAAAAEAAAAAAAgAAAAAAAAIAAAAAAA=</HashCode>
-      <FileName>TextWriterLogger.cs</FileName>
-    </TypeIdentifier>
-    <Lollipop Position="0.2" />
-  </Class>
-  <Class Name="TerminalGuiFluentTesting.NetSequences">
-    <Position X="11" Y="4.5" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAIAAAAAAAAAAAAAAAAAAAAAAAAACACAAAAAAgI=</HashCode>
-      <FileName>NetSequences.cs</FileName>
-    </TypeIdentifier>
-  </Class>
-  <Enum Name="TerminalGuiFluentTesting.V2TestDriver">
-    <Position X="9.25" Y="4.5" Width="1.5" />
-    <TypeIdentifier>
-      <HashCode>AAAAAAAAAAAAAAAAAAAAAAAAAAgAAAAAAAAAAAACAAA=</HashCode>
-      <FileName>V2TestDriver.cs</FileName>
-    </TypeIdentifier>
-  </Enum>
-  <Font Name="Segoe UI" Size="9" />
-</ClassDiagram>

docfx/docs/application.md

@@ -18,7 +18,7 @@ Terminal.Gui v2 uses an instance-based application architecture with the **IRunn
 graph TB
     subgraph ViewTree["View Hierarchy (SuperView/SubView)"]
         direction TB
-        Top[app.Current<br/>Window]
+        Top[app.TopRunnable<br/>Window]
         Menu[MenuBar]
         Status[StatusBar]
         Content[Content View]
@@ -59,19 +59,19 @@ sequenceDiagram
     
     App->>Main: Run(mainWindow)
     activate Main
-    Note over App: SessionStack: [Main]<br/>Current: Main
+    Note over App: SessionStack: [Main]<br/>TopRunnable: Main
     
     Main->>Dialog: Run(dialog)
     activate Dialog
-    Note over App: SessionStack: [Dialog, Main]<br/>Current: Dialog
+    Note over App: SessionStack: [Dialog, Main]<br/>TopRunnable: Dialog
     
     Dialog->>App: RequestStop()
     deactivate Dialog
-    Note over App: SessionStack: [Main]<br/>Current: Main
+    Note over App: SessionStack: [Main]<br/>TopRunnable: Main
     
     Main->>App: RequestStop()
     deactivate Main
-    Note over App: SessionStack: []<br/>Current: null
+    Note over App: SessionStack: []<br/>TopRunnable: null
 ```
 
 ## Key Concepts
@@ -82,37 +82,37 @@ sequenceDiagram
 
 ```csharp
 // OLD (v1 / early v2 - still works but obsolete):
-Application.Init();
-var top = new Window();
-top.Add(myView);
-Application.Run(top);
-top.Dispose();
-Application.Shutdown(); // Obsolete - use Dispose() instead
+Application.Init ();
+Window top = new ();
+top.Add (myView);
+Application.Run (top);
+top.Dispose ();
+Application.Shutdown (); // Obsolete - use Dispose() instead
 
 // RECOMMENDED (v2 - instance-based with using statement):
-using (var app = Application.Create().Init())
+using (IApplication app = Application.Create ().Init ())
 {
-    var top = new Window();
-    top.Add(myView);
-    app.Run(top);
-    top.Dispose();
+    Window top = new ();
+    top.Add (myView);
+    app.Run (top);
+    top.Dispose ();
 } // app.Dispose() called automatically
 
 // WITH IRunnable (fluent API with automatic disposal):
-using (var app = Application.Create().Init())
+using (IApplication app = Application.Create ().Init ())
 {
-    app.Run<ColorPickerDialog>();
-    Color? result = app.GetResult<Color>();
+    app.Run<ColorPickerDialog> ();
+    Color? result = app.GetResult<Color> ();
 }
 
 // SIMPLEST (manual disposal):
-var app = Application.Create().Init();
-app.Run<ColorPickerDialog>();
-Color? result = app.GetResult<Color>();
-app.Dispose();
+IApplication app = Application.Create ().Init ();
+app.Run<ColorPickerDialog> ();
+Color? result = app.GetResult<Color> ();
+app.Dispose ();
 ```
 
-**Note:** The static `Application` class delegates to `ApplicationImpl.Instance` (a singleton). `Application.Create()` creates a **new** `ApplicationImpl` instance, enabling multiple application contexts and better testability.
+**Note:** The static `Application` class delegates to a singleton instance accessible via `Application.Instance`. `Application.Create()` creates a **new** application instance, enabling multiple application contexts and better testability.
 
 ### View.App Property
 
@@ -130,7 +130,7 @@ public class View
     /// Gets the application context, checking parent hierarchy if needed.
     /// Override to customize application resolution.
     /// </summary>
-    public virtual IApplication? GetApp() => App ?? SuperView?.GetApp();
+    public virtual IApplication? GetApp () => App ?? SuperView?.GetApp ();
 }
 ```
 
@@ -147,10 +147,10 @@ public class View
 ```csharp
 public class MyView : View
 {
-    public override void OnEnter(View view)
+    public override void OnEnter (View view)
     {
         // Use View.App instead of static Application
-        App?.Current?.SetNeedsDraw();
+        App?.TopRunnable?.SetNeedsDraw ();
         
         // Access SessionStack
         if (App?.SessionStack.Count > 0)
@@ -168,15 +168,15 @@ public class MyView : View
 {
     private readonly IApplication _app;
     
-    public MyView(IApplication app)
+    public MyView (IApplication app)
     {
         _app = app;
         // Now completely decoupled from static Application
     }
     
-    public void DoWork()
+    public void DoWork ()
     {
-        _app.Current?.SetNeedsDraw();
+        _app.TopRunnable?.SetNeedsDraw ();
     }
 }
 ```
@@ -199,26 +199,26 @@ The fluent API enables elegant method chaining with automatic resource managemen
 
 ```csharp
 // Recommended: using statement with GetResult
-using (var app = Application.Create().Init())
+using (IApplication app = Application.Create ().Init ())
 {
-    app.Run<ColorPickerDialog>();
-    Color? result = app.GetResult<Color>();
+    app.Run<ColorPickerDialog> ();
+    Color? result = app.GetResult<Color> ();
     
     if (result is { })
     {
-        ApplyColor(result);
+        ApplyColor (result);
     }
 }
 
 // Alternative: Manual disposal
-var app = Application.Create().Init();
-app.Run<ColorPickerDialog>();
-Color? result = app.GetResult<Color>();
-app.Dispose();
+IApplication app = Application.Create ().Init ();
+app.Run<ColorPickerDialog> ();
+Color? result = app.GetResult<Color> ();
+app.Dispose ();
 
 if (result is { })
 {
-    ApplyColor(result);
+    ApplyColor (result);
 }
 ```
 
@@ -240,19 +240,19 @@ if (result is { })
 
 ```csharp
 // Framework ownership - automatic disposal
-using (var app = Application.Create().Init())
+using (IApplication app = Application.Create ().Init ())
 {
-    app.Run<MyDialog>(); // Dialog disposed automatically when Run returns
-    var result = app.GetResult<MyResultType>();
+    app.Run<MyDialog> (); // Dialog disposed automatically when Run returns
+    MyResultType? result = app.GetResult<MyResultType> ();
 }
 
 // Caller ownership - manual disposal
-using (var app = Application.Create().Init())
+using (IApplication app = Application.Create ().Init ())
 {
-    var dialog = new MyDialog();
-    app.Run(dialog);
-    var result = dialog.Result;
-    dialog.Dispose();  // Caller must dispose
+    MyDialog dialog = new ();
+    app.Run (dialog);
+    MyResultType? result = dialog.Result;
+    dialog.Dispose ();  // Caller must dispose
 }
 ```
 
@@ -265,35 +265,36 @@ public class FileDialog : Runnable<string?>
 {
     private TextField _pathField;
     
-    public FileDialog()
+    public FileDialog ()
     {
         Title = "Select File";
         
-        _pathField = new TextField { X = 1, Y = 1, Width = Dim.Fill(1) };
+        _pathField = new () { X = 1, Y = 1, Width = Dim.Fill (1) };
         
-        var okButton = new Button { Text = "OK", IsDefault = true };
-        okButton.Accepting += (s, e) => {
+        Button okButton = new () { Text = "OK", IsDefault = true };
+        okButton.Accepting += (s, e) =>
+        {
             Result = _pathField.Text;
-            Application.RequestStop();
+            Application.RequestStop ();
         };
         
-        Add(_pathField, okButton);
+        Add (_pathField, okButton);
     }
     
-    protected override bool OnIsRunningChanging(bool oldValue, bool newValue)
+    protected override bool OnIsRunningChanging (bool oldValue, bool newValue)
     {
         if (!newValue)  // Stopping - extract result before disposal
         {
             Result = _pathField?.Text;
         }
-        return base.OnIsRunningChanging(oldValue, newValue);
+        return base.OnIsRunningChanging (oldValue, newValue);
     }
 }
 ```
 
 ### Lifecycle Properties
 
-- **`IsRunning`** - True when runnable is on `RunnableSessionStack`
+- **`IsRunning`** - True when runnable is on `SessionStack`
 - **`IsModal`** - True when runnable is at top of stack (capturing all input)
 - **`Result`** - Typed result value set before stopping
 
@@ -310,7 +311,7 @@ All events follow Terminal.Gui's Cancellable Work Pattern:
 **Example - Result Extraction:**
 
 ```csharp
-protected override bool OnIsRunningChanging(bool oldValue, bool newValue)
+protected override bool OnIsRunningChanging (bool oldValue, bool newValue)
 {
     if (!newValue)  // Stopping
     {
@@ -318,33 +319,39 @@ protected override bool OnIsRunningChanging(bool oldValue, bool newValue)
         Result = _colorPicker.SelectedColor;
         
         // Optionally cancel stop (e.g., unsaved changes)
-        if (HasUnsavedChanges())
+        if (HasUnsavedChanges ())
         {
-            int response = MessageBox.Query("Save?", "Save changes?", "Yes", "No", "Cancel");
-            if (response == 2) return true;  // Cancel stop
-            if (response == 0) Save();
+            var response = MessageBox.Query ("Save?", "Save changes?", "Yes", "No", "Cancel");
+            if (response == 2)
+            {
+                return true;  // Cancel stop
+            }
+            if (response == 0)
+            {
+                Save ();
+            }
         }
     }
     
-    return base.OnIsRunningChanging(oldValue, newValue);
+    return base.OnIsRunningChanging (oldValue, newValue);
 }
 ```
 
-### RunnableSessionStack
+### SessionStack
 
-The `RunnableSessionStack` manages all running `IRunnable` sessions:
+The `SessionStack` manages all running `IRunnable` sessions:
 
 ```csharp
 public interface IApplication
 {
     /// <summary>
     /// Stack of running IRunnable sessions.
-    /// Each entry is a RunnableSessionToken wrapping an IRunnable.
+    /// Each entry is a SessionToken wrapping an IRunnable.
     /// </summary>
-    ConcurrentStack<RunnableSessionToken>? RunnableSessionStack { get; }
+    ConcurrentStack<SessionToken>? SessionStack { get; }
     
     /// <summary>
-    /// The IRunnable at the top of RunnableSessionStack (currently modal).
+    /// The IRunnable at the top of SessionStack (currently modal).
     /// </summary>
     IRunnable? TopRunnable { get; }
 }
@@ -353,9 +360,9 @@ public interface IApplication
 **Stack Behavior:**
 
 - Push: `Begin(IRunnable)` adds to top of stack
-- Pop: `End(RunnableSessionToken)` removes from stack
+- Pop: `End(SessionToken)` removes from stack
 - Peek: `TopRunnable` returns current modal runnable
-- All: `RunnableSessionStack` enumerates all running sessions
+- All: `SessionStack` enumerates all running sessions
 
 ## IApplication Interface
 
@@ -374,19 +381,19 @@ public interface IApplication
     IMainLoopCoordinator? Coordinator { get; }
     
     // Fluent API methods  
-    IApplication Init(string? driverName = null);
-    void Dispose(); // IDisposable
+    IApplication Init (string? driverName = null);
+    void Dispose (); // IDisposable
     
     // Runnable methods
-    SessionToken? Begin(IRunnable runnable);
-    object? Run(IRunnable runnable, Func<Exception, bool>? errorHandler = null);
-    IApplication Run<TRunnable>(Func<Exception, bool>? errorHandler = null) where TRunnable : IRunnable, new();
-    void RequestStop(IRunnable? runnable);
-    void End(SessionToken sessionToken);
+    SessionToken? Begin (IRunnable runnable);
+    object? Run (IRunnable runnable, Func<Exception, bool>? errorHandler = null);
+    IApplication Run<TRunnable> (Func<Exception, bool>? errorHandler = null) where TRunnable : IRunnable, new();
+    void RequestStop (IRunnable? runnable);
+    void End (SessionToken sessionToken);
     
     // Result extraction
-    object? GetResult();
-    T? GetResult<T>() where T : class;
+    object? GetResult ();
+    T? GetResult<T> () where T : class;
     
     // ... other members
 }
@@ -423,13 +430,13 @@ The `SessionStack` property is the stack of running sessions:
 
 ```csharp
 // Access all running sessions
-foreach (var runnable in app.SessionStack)
+foreach (SessionToken runnable in app.SessionStack)
 {
     // Process each session
 }
 
 // From within a view
-int sessionCount = App?.SessionStack.Count ?? 0;
+var sessionCount = App?.SessionStack.Count ?? 0;
 ```
 
 **Why "SessionStack" instead of "Runnables"?**
@@ -439,25 +446,25 @@ int sessionCount = App?.SessionStack.Count ?? 0;
 
 ## Migration from Static Application
 
-The static `Application` class delegates to `ApplicationImpl.Instance` (a singleton) and is marked obsolete. All static methods and properties are marked with `[Obsolete]` but remain functional for backward compatibility:
+The static `Application` class delegates to a singleton instance and is marked obsolete. All static methods and properties are marked with `[Obsolete]` but remain functional for backward compatibility:
 
 ```csharp
 public static partial class Application
 {
-    [Obsolete("The legacy static Application object is going away.")]
-    public static View? TopRunnableView => ApplicationImpl.Instance.TopRunnableView;
+    [Obsolete ("The legacy static Application object is going away.")]
+    public static View? TopRunnableView => Instance.TopRunnableView;
     
-    [Obsolete("The legacy static Application object is going away.")]
-    public static IRunnable? TopRunnable => ApplicationImpl.Instance.TopRunnable;
+    [Obsolete ("The legacy static Application object is going away.")]
+    public static IRunnable? TopRunnable => Instance.TopRunnable;
     
-    [Obsolete("The legacy static Application object is going away.")]
-    public static ConcurrentStack<SessionToken>? SessionStack => ApplicationImpl.Instance.SessionStack;
+    [Obsolete ("The legacy static Application object is going away.")]
+    public static ConcurrentStack<SessionToken>? SessionStack => Instance.SessionStack;
     
     // ... other obsolete static members
 }
 ```
 
-**Important:** The static `Application` class uses a singleton (`ApplicationImpl.Instance`), while `Application.Create()` creates new instances. For new code, prefer the instance-based pattern using `Application.Create()`.
+**Important:** The static `Application` class uses a singleton (`Application.Instance`), while `Application.Create()` creates new instances. For new code, prefer the instance-based pattern using `Application.Create()`.
 
 ### Migration Strategies
 
@@ -465,15 +472,15 @@ public static partial class Application
 
 ```csharp
 // OLD:
-void MyMethod()
+void MyMethod ()
 {
-    Application.TopRunnable?.SetNeedsDraw();
+    Application.TopRunnable?.SetNeedsDraw ();
 }
 
 // NEW:
-void MyMethod(View view)
+void MyMethod (View view)
 {
-    view.App?.TopRunnableView?.SetNeedsDraw();
+    view.App?.TopRunnableView?.SetNeedsDraw ();
 }
 ```
 
@@ -481,18 +488,18 @@ void MyMethod(View view)
 
 ```csharp
 // OLD:
-void ProcessSessions()
+void ProcessSessions ()
 {
-    foreach (var runnable in Application.SessionStack)
+    foreach (SessionToken runnable in Application.SessionStack)
     {
         // Process
     }
 }
 
 // NEW:
-void ProcessSessions(IApplication app)
+void ProcessSessions (IApplication app)
 {
-    foreach (var runnable in app.SessionStack)
+    foreach (SessionToken runnable in app.SessionStack)
     {
         // Process
     }
@@ -506,14 +513,14 @@ public class MyService
 {
     private readonly IApplication _app;
     
-    public MyService(IApplication app)
+    public MyService (IApplication app)
     {
         _app = app;
     }
     
-    public void DoWork()
+    public void DoWork ()
     {
-        _app.Current?.Title = "Processing...";
+        _app.TopRunnable?.Title = "Processing...";
     }
 }
 ```
@@ -530,9 +537,9 @@ Terminal.Gui v2 implements the `IDisposable` pattern for proper resource cleanup
 
 ```csharp
 // Automatic disposal with using statement
-using (var app = Application.Create().Init())
+using (IApplication app = Application.Create ().Init ())
 {
-    app.Run<MyDialog>();
+    app.Run<MyDialog> ();
     // app.Dispose() automatically called when scope exits
 }
 ```
@@ -541,15 +548,15 @@ using (var app = Application.Create().Init())
 
 ```csharp
 // Manual disposal
-var app = Application.Create();
+IApplication app = Application.Create ();
 try
 {
-    app.Init();
-    app.Run<MyDialog>();
+    app.Init ();
+    app.Run<MyDialog> ();
 }
 finally
 {
-    app.Dispose(); // Ensure cleanup even if exception occurs
+    app.Dispose (); // Ensure cleanup even if exception occurs
 }
 ```
 
@@ -561,44 +568,44 @@ finally
 
 ```csharp
 // RECOMMENDED (using statement):
-using (var app = Application.Create().Init())
+using (IApplication app = Application.Create ().Init ())
 {
-    app.Run<MyDialog>();
-    var result = app.GetResult<MyResult>();
+    app.Run<MyDialog> ();
+    MyResult? result = app.GetResult<MyResult> ();
     // app.Dispose() called automatically here
 }
 
 // ALTERNATIVE (manual disposal):
-var app = Application.Create().Init();
-app.Run<MyDialog>();
-var result = app.GetResult<MyResult>();
-app.Dispose(); // Must call explicitly
+IApplication app = Application.Create ().Init ();
+app.Run<MyDialog> ();
+MyResult? result = app.GetResult<MyResult> ();
+app.Dispose (); // Must call explicitly
 
 // OLD (obsolete - do not use):
-var result = app.Run<MyDialog>().Shutdown() as MyResult;
+object? result = app.Run<MyDialog> ().Shutdown ();
 ```
 
 ### Input Thread Lifecycle
 
-When you call `Init()`, Terminal.Gui starts a dedicated input thread that continuously polls for console input. This thread must be stopped properly:
+When calling `Init()`, Terminal.Gui starts a dedicated input thread that continuously polls for console input. This thread must be stopped properly:
 
 ```csharp
-var app = Application.Create();
-app.Init("fake"); // Input thread starts here
+IApplication app = Application.Create ();
+app.Init ("fake"); // Input thread starts here
 
 // Input thread runs in background at ~50 polls/second (20ms throttle)
 
-app.Dispose(); // Cancels input thread and waits for it to exit
+app.Dispose (); // Cancels input thread and waits for it to exit
 ```
 
 **Important for Tests**: Always dispose applications in tests to prevent thread leaks:
 
 ```csharp
 [Fact]
-public void My_Test()
+public void My_Test ()
 {
-    using var app = Application.Create();
-    app.Init("fake");
+    using IApplication app = Application.Create ();
+    app.Init ("fake");
     
     // Test code here
     
@@ -612,22 +619,22 @@ The legacy static `Application` singleton can be re-initialized after disposal (
 
 ```csharp
 // Test 1
-Application.Init();
-Application.Shutdown(); // Obsolete but still works for legacy singleton
+Application.Init ();
+Application.Shutdown (); // Obsolete but still works for legacy singleton
 
 // Test 2 - singleton resets and can be re-initialized
-Application.Init(); // ✅ Works!
-Application.Shutdown(); // Obsolete but still works for legacy singleton
+Application.Init (); // ✅ Works!
+Application.Shutdown (); // Obsolete but still works for legacy singleton
 ```
 
 However, instance-based applications follow standard `IDisposable` semantics and cannot be reused after disposal:
 
 ```csharp
-var app = Application.Create();
-app.Init();
-app.Dispose();
+IApplication app = Application.Create ();
+app.Init ();
+app.Dispose ();
 
-app.Init(); // ❌ Throws ObjectDisposedException
+app.Init (); // ❌ Throws ObjectDisposedException
 ```
 
 ## Session Management
@@ -637,21 +644,21 @@ app.Init(); // ❌ Throws ObjectDisposedException
 Applications manage sessions through `Begin()` and `End()`:
 
 ```csharp
-using var app = Application.Create ();
-app.Init();
+using IApplication app = Application.Create ();
+app.Init ();
 
-var window = new Window();
+Window window = new ();
 
 // Begin a new session - pushes to SessionStack
-SessionToken? token = app.Begin(window);
+SessionToken? token = app.Begin (window);
 
 // TopRunnable now points to this window
-Debug.Assert(app.TopRunnable == window);
+Debug.Assert (app.TopRunnable == window);
 
 // End the session - pops from SessionStack
 if (token != null)
 {
-    app.End(token);
+    app.End (token);
 }
 
 // TopRunnable restored to previous runnable (if any)
@@ -662,25 +669,25 @@ if (token != null)
 Multiple sessions can run nested:
 
 ```csharp
-using var app = Application.Create ();
-app.Init();
+using IApplication app = Application.Create ();
+app.Init ();
 
 // Session 1
-var main = new Window { Title = "Main" };
-var token1 = app.Begin(main);
+Window main = new () { Title = "Main" };
+SessionToken? token1 = app.Begin (main);
 // app.TopRunnable == main, SessionStack.Count == 1
 
 // Session 2 (nested)
-var dialog = new Dialog { Title = "Dialog" };
-var token2 = app.Begin(dialog);
+Dialog dialog = new () { Title = "Dialog" };
+SessionToken? token2 = app.Begin (dialog);
 // app.TopRunnable == dialog, SessionStack.Count == 2
 
 // End dialog
-app.End(token2);
+app.End (token2);
 // app.TopRunnable == main, SessionStack.Count == 1
 
 // End main
-app.End(token1);
+app.End (token1);
 // app.TopRunnable == null, SessionStack.Count == 0
 ```
 
@@ -694,24 +701,24 @@ public class View
     /// <summary>
     /// Gets the driver for this view.
     /// </summary>
-    public IDriver? Driver => GetDriver();
+    public IDriver? Driver => GetDriver ();
     
     /// <summary>
     /// Gets the driver, checking application context if needed.
     /// Override to customize driver resolution.
     /// </summary>
-    public virtual IDriver? GetDriver() => App?.Driver;
+    public virtual IDriver? GetDriver () => App?.Driver;
 }
 ```
 
 **Usage:**
 
 ```csharp
-public override void OnDrawContent(Rectangle viewport)
+public override void OnDrawContent (Rectangle viewport)
 {
     // Use view's driver instead of Application.Driver
-    Driver?.Move(0, 0);
-    Driver?.AddStr("Hello");
+    Driver?.Move (0, 0);
+    Driver?.AddStr ("Hello");
 }
 ```
 
@@ -723,44 +730,44 @@ The instance-based architecture dramatically improves testability:
 
 ```csharp
 [Fact]
-public void MyView_DisplaysCorrectly()
+public void MyView_DisplaysCorrectly ()
 {
     // Create mock application
-    var mockApp = new Mock<IApplication>();
-    mockApp.Setup(a => a.Current).Returns(new Runnable());
+    Mock<IApplication> mockApp = new ();
+    mockApp.Setup (a => a.TopRunnable).Returns (new Runnable ());
     
     // Create view with mock app
-    var view = new MyView { App = mockApp.Object };
+    MyView view = new () { App = mockApp.Object };
     
     // Test without Application.Init()!
-    view.SetNeedsDraw();
-    Assert.True(view.NeedsDraw);
+    view.SetNeedsDraw ();
+    Assert.True (view.NeedsDraw);
     
     // No Application.Shutdown() needed!
 }
 ```
 
-### Testing with Real ApplicationImpl
+### Testing with Real Application
 
 ```csharp
 [Fact]
-public void MyView_WorksWithRealApplication()
+public void MyView_WorksWithRealApplication ()
 {
-    using var app = Application.Create ();
-    app.Init("fake");
+    using IApplication app = Application.Create ();
+    app.Init ("fake");
     
-    var view = new MyView();
-    var top = new Window();
-    top.Add(view);
+    MyView view = new ();
+    Window top = new ();
+    top.Add (view);
     
-    app.Begin(top);
+    app.Begin (top);
     
     // View.App automatically set
-    Assert.NotNull(view.App);
-    Assert.Same(app, view.App);
+    Assert.NotNull (view.App);
+    Assert.Same (app, view.App);
     
     // Test view behavior
-    view.DoSomething();
+    view.DoSomething ();
 }
 ```
 
@@ -770,9 +777,9 @@ public void MyView_WorksWithRealApplication()
 
 ```csharp
 ✅ GOOD:
-public void Refresh()
+public void Refresh ()
 {
-    App?.TopRunnableView?.SetNeedsDraw();
+    App?.TopRunnableView?.SetNeedsDraw ();
 }
 ```
 
@@ -780,9 +787,9 @@ public void Refresh()
 
 ```csharp
 ❌ AVOID:
-public void Refresh()
+public void Refresh ()
 {
-    Application.TopRunnableView?.SetNeedsDraw(); // Obsolete!
+    Application.TopRunnableView?.SetNeedsDraw (); // Obsolete!
 }
 ```
 
@@ -792,7 +799,7 @@ public void Refresh()
 ✅ GOOD:
 public class Service
 {
-    public Service(IApplication app) { }
+    public Service (IApplication app) { }
 }
 ```
 
@@ -800,15 +807,15 @@ public class Service
 
 ```csharp
 ❌ AVOID (obsolete pattern):
-public void Refresh()
+public void Refresh ()
 {
-    Application.TopRunnableView?.SetNeedsDraw(); // Obsolete static access
+    Application.TopRunnableView?.SetNeedsDraw (); // Obsolete static access
 }
 
 ✅ PREFERRED:
-public void Refresh()
+public void Refresh ()
 {
-    App?.TopRunnableView?.SetNeedsDraw(); // Use View.App property
+    App?.TopRunnableView?.SetNeedsDraw (); // Use View.App property
 }
 ```
 
@@ -820,9 +827,9 @@ public class SpecialView : View
 {
     private IApplication? _customApp;
     
-    public override IApplication? GetApp()
+    public override IApplication? GetApp ()
     {
-        return _customApp ?? base.GetApp();
+        return _customApp ?? base.GetApp ();
     }
 }
 ```
@@ -835,15 +842,15 @@ The instance-based architecture enables multiple applications:
 
 ```csharp
 // Application 1
-using var app1 = Application.Create ();
-app1.Init("windows");
-var top1 = new Window { Title = "App 1" };
+using IApplication app1 = Application.Create ();
+app1.Init ("windows");
+Window top1 = new () { Title = "App 1" };
 // ... configure top1
 
 // Application 2 (different driver!)
-using var app2 = Application.Create ();
-app2.Init("unix");
-var top2 = new Window { Title = "App 2" };
+using IApplication app2 = Application.Create ();
+app2.Init ("unix");
+Window top2 = new () { Title = "App 2" };
 // ... configure top2
 
 // Views in top1 use app1
@@ -857,14 +864,14 @@ Create views that work with any application:
 ```csharp
 public class UniversalView : View
 {
-    public void ShowMessage(string message)
+    public void ShowMessage (string message)
     {
         // Works regardless of which application context
-        var app = GetApp();
+        IApplication? app = GetApp ();
         if (app != null)
         {
-            var msg = new MessageBox(message);
-            app.Begin(msg);
+            MessageBox msg = new (message);
+            app.Begin (msg);
         }
     }
 }

docfx/docs/drivers.md

@@ -97,7 +97,7 @@ The driver architecture employs a **multi-threaded design** for optimal responsi
 
 ```
 ┌─────────────────────────────────────────────┐
-│         ApplicationImpl.Init()              │
+│         IApplication.Init()              │
 │  Creates MainLoopCoordinator<T> with        │
 │  ComponentFactory<T>                        │
 └────────────────┬────────────────────────────┘
@@ -128,7 +128,7 @@ This separation ensures that input is never lost and the UI remains responsive d
 
 When you call `Application.Init()`:
 
-1. **ApplicationImpl.Init()** is invoked
+1. **IApplication.Init()** is invoked
 2. Creates a `MainLoopCoordinator<T>` with the appropriate `ComponentFactory<T>`
 3. **MainLoopCoordinator.StartAsync()** begins:
    - Starts the input thread which creates `IInput<T>`
@@ -220,6 +220,5 @@ This ensures Terminal.Gui applications can be debugged directly in Visual Studio
 ## See Also
 
 - @Terminal.Gui.Drivers - API Reference
-- @Terminal.Gui.App.Application - Application class
-- @Terminal.Gui.App.ApplicationImpl - Application implementation
+- @Terminal.Gui.App.IApplication - Application interface
 - @Terminal.Gui.App.MainLoopCoordinator`1 - Main loop coordination

docfx/docs/keyboard.md

@@ -230,7 +230,7 @@ The @Terminal.Gui.App.Keyboard class implements @Terminal.Gui.App.IKeyboard and
 - **Events**: KeyDown, KeyUp events for application-level keyboard monitoring
 - **Command Implementations**: Handlers for Application-scoped commands (Quit, Suspend, Navigation, Refresh, Arrange)
 
-The @Terminal.Gui.App.ApplicationImpl class creates and manages the @Terminal.Gui.App.IKeyboard instance, setting its `IApplication` property to `this` to provide the necessary @Terminal.Gui.App.IApplication reference.
+The @Terminal.Gui.App.IApplication implementations create and manage the @Terminal.Gui.App.IKeyboard instance, setting its `IApplication` property to `this` to provide the necessary @Terminal.Gui.App.IApplication reference.
 
 ## Driver