Fix more issue in the layout.

Terminal.Gui/View/View.cs

@@ -2656,12 +2656,21 @@ namespace Terminal.Gui {
 			}
 
 			if (edges.Any ()) {
-				(var from, var to) = edges.First ();
-				if (from != superView?.GetTopSuperView (to, from) && !ReferenceEquals (from, to)) {
-					if (ReferenceEquals (from.SuperView, to)) {
-						throw new InvalidOperationException ($"ComputedLayout for \"{superView}\": \"{to}\" references a SubView (\"{from}\").");
-					} else {
-						throw new InvalidOperationException ($"ComputedLayout for \"{superView}\": \"{from}\" linked with \"{to}\" was not found. Did you forget to add it to {superView}?");
+				foreach ((var from, var to) in edges) {
+					if (from == to || from?.SuperView == to?.SuperView) {
+						// if not yet added to the result, add it and remove from edge
+						if (result.Find (v => v == from) == null) {
+							result.Add (from);
+						} else if (result.Find (v => v == to) == null) {
+							result.Add (to);
+						}
+						edges.Remove ((from, to));
+					} else if (from != superView?.GetTopSuperView (to, from) && !ReferenceEquals (from, to)) {
+						if (ReferenceEquals (from.SuperView, to)) {
+							throw new InvalidOperationException ($"ComputedLayout for \"{superView}\": \"{to}\" references a SubView (\"{from}\").");
+						} else {
+							throw new InvalidOperationException ($"ComputedLayout for \"{superView}\": \"{from}\" linked with \"{to}\" was not found. Did you forget to add it to {superView}?");
+						}
 					}
 				}
 			}
@@ -2740,11 +2749,10 @@ namespace Terminal.Gui {
 
 			// If the 'to' is rooted to 'from' and the layoutstyle is Computed it's a special-case.
 			// Use LayoutSubview with the Frame of the 'from' 
-			if (SuperView != null && GetTopSuperView () != null && LayoutNeeded
-			    && ordered.Count == 0 && edges.Count > 0 && LayoutStyle == LayoutStyle.Computed) {
-
-				(var from, var to) = edges.First ();
-				LayoutSubview (to, from.Frame);
+			if (SuperView != null && GetTopSuperView () != null && LayoutNeeded && edges.Count > 0) {
+				foreach ((var from, var to) in edges) {
+					LayoutSubview (to, from.Frame);
+				}
 			}
 
 			LayoutNeeded = false;

UICatalog/Scenarios/ColorPicker.cs

@@ -39,23 +39,20 @@ namespace UICatalog.Scenarios {
 			// Scenario Window's.
 			Win.Title = this.GetName ();
 
-			// Forground ColorPicker.
+			// Foreground ColorPicker.
 			foregroundColorPicker = new ColorPicker ("Foreground Color");
-			foregroundColorPicker.X = 0;
-			foregroundColorPicker.Y = 0;
 			foregroundColorPicker.ColorChanged += ForegroundColor_ColorChanged;
 			Win.Add (foregroundColorPicker);
 
-			foregroundColorLabel = new Label ();
-			foregroundColorLabel.X = Pos.Left(foregroundColorPicker);
-			foregroundColorLabel.Y = Pos.Bottom (foregroundColorPicker) + 1;
+			foregroundColorLabel = new Label {
+				X = Pos.Left (foregroundColorPicker),
+				Y = Pos.Bottom (foregroundColorPicker) + 1
+			};
 			Win.Add (foregroundColorLabel);
 
 			// Background ColorPicker.
-			backgroundColorPicker = new ColorPicker ();
-			backgroundColorPicker.Text = "Background Color";
+			backgroundColorPicker = new ColorPicker ("Background Color");
 			backgroundColorPicker.X = Pos.AnchorEnd () - (Pos.Right (backgroundColorPicker) - Pos.Left (backgroundColorPicker));
-			backgroundColorPicker.Y = 0;
 			backgroundColorPicker.ColorChanged += BackgroundColor_ColorChanged;
 			Win.Add (backgroundColorPicker);
 

UICatalog/Scenarios/ViewExperiments.cs

@@ -120,7 +120,7 @@ namespace UICatalog.Scenarios {
 				};
 				Add (copyTop);
 
-				LayoutSubviews ();
+				//LayoutSubviews ();
 				Height = Margin.Thickness.Vertical + BorderFrame.Thickness.Vertical + Padding.Thickness.Vertical + 4;
 				Width = 20;
 			}
@@ -234,7 +234,7 @@ namespace UICatalog.Scenarios {
 				//};
 				//Add (rbBorderBrush);
 
-				Height = 8; 
+				Height = 8;
 				Title = title;
 			}
 		}
@@ -242,7 +242,6 @@ namespace UICatalog.Scenarios {
 		public override void Init ()
 		{
 			Application.Init ();
-			//Application.Init ();
 			ConfigurationManager.Themes.Theme = Theme;
 			ConfigurationManager.Apply ();
 			Application.Top.ColorScheme = Colors.ColorSchemes [TopLevelColorScheme];

UnitTests/View/Layout/DimTests.cs

@@ -544,12 +544,11 @@ namespace Terminal.Gui.ViewTests {
 		//	Assert.Throws<InvalidOperationException> (() => super.LayoutSubviews ());
 		//}
 
-
 		/// <summary>
 		/// This is an intentionally obtuse test. See https://github.com/gui-cs/Terminal.Gui/issues/2461
 		/// </summary>
 		[Fact]
-		public void DimCombine_ObtuseScenario_Does_Not_Throw ()
+		public void DimCombine_ObtuseScenario_Throw ()
 		{
 			var t = new View ("top") { Width = 80, Height = 25 };
 
@@ -571,11 +570,12 @@ namespace Terminal.Gui.ViewTests {
 			w.Add (f);
 			t.Add (w);
 
-			// BUGBUG: v2 - f references t here; t is f's super-superview. This is not supported!
+			// BUGBUG: v2 - f references t here; t is f's super-superview. This is supported!
+			// BUGBUG: v2 - f references v2 here; v2 is f's subview. This is not supported!
 			f.Width = Dim.Width (t) - Dim.Width (v2);      // 80 - 74 = 6
 			f.Height = Dim.Height (t) - Dim.Height (v2);   // 25 - 19 = 6
 
-			t.LayoutSubviews ();
+			Assert.Throws<InvalidOperationException> (t.LayoutSubviews);
 			Assert.Equal (80, t.Frame.Width);
 			Assert.Equal (25, t.Frame.Height);
 			Assert.Equal (78, w.Frame.Width);
@@ -583,10 +583,10 @@ namespace Terminal.Gui.ViewTests {
 			// BUGBUG: v2 - this no longer works - see above
 			//Assert.Equal (6, f.Frame.Width);
 			//Assert.Equal (6, f.Frame.Height);
-			Assert.Equal (76, v1.Frame.Width);
-			Assert.Equal (21, v1.Frame.Height);
-			Assert.Equal (74, v2.Frame.Width);
-			Assert.Equal (19, v2.Frame.Height);
+			//Assert.Equal (76, v1.Frame.Width);
+			//Assert.Equal (21, v1.Frame.Height);
+			//Assert.Equal (74, v2.Frame.Width);
+			//Assert.Equal (19, v2.Frame.Height);
 		}
 
 		[Fact]

UnitTests/View/Layout/PosTests.cs

@@ -1039,5 +1039,33 @@ namespace Terminal.Gui.ViewTests {
 				Assert.Equal (61, label.Frame.Y);
 			}
 		}
+
+		[Fact]
+		public void PosCombine_Referencing_Same_View ()
+		{
+			var super = new View ("super") {
+				Width = 10,
+				Height = 10
+			};
+			var view1 = new View ("view1") {
+				Width = 2,
+				Height = 2,
+			};
+			var view2 = new View ("view2") {
+				Width = 2,
+				Height = 2,
+			};
+			view2.X = Pos.AnchorEnd () - (Pos.Right (view2) - Pos.Left (view2));
+
+			super.Add (view1, view2);
+			super.BeginInit ();
+			super.EndInit ();
+
+			var exception = Record.Exception (super.LayoutSubviews);
+			Assert.Null (exception);
+			Assert.Equal (new Rect (0, 0, 10, 10), super.Frame);
+			Assert.Equal (new Rect (0, 0, 2, 2), view1.Frame);
+			Assert.Equal (new Rect (8, 0, 2, 2), view2.Frame);
+		}
 	}
 }