[Net10] OnSizeAllocated in Shell not triggered - fix

src/Controls/src/Core/Compatibility/Handlers/Shell/Android/ShellFlyoutRenderer.cs

@@ -407,6 +407,15 @@ void UpdateScrim(Brush backdrop)
 			}
 		}
 
+		protected override void OnLayout(bool changed, int left, int top, int right, int bottom)
+		{
+			base.OnLayout(changed, left, top, right, bottom);
+
+			var destination = Context.ToCrossPlatformRectInReferenceFrame(left, top, right, bottom);
+			if (Shell.Frame != destination)
+				Shell.Frame = destination;
+		}
+
 		internal void Disconnect()
 		{
 			ShellController?.RemoveAppearanceObserver(this);

src/Controls/src/Core/Compatibility/Handlers/Shell/iOS/ShellRenderer.cs

@@ -141,6 +141,10 @@ public override void ViewDidLayoutSubviews()
 			base.ViewDidLayoutSubviews();
 			if (_currentShellItemRenderer != null)
 				_currentShellItemRenderer.ViewController.View.Frame = View.Bounds;
+
+			var destination = View.Bounds.ToRectangle();
+			if (Shell.Frame != destination)
+				Shell.Frame = destination;
 		}
 
 		public override void ViewDidLoad()

src/Controls/src/Core/PublicAPI/net-android/PublicAPI.Unshipped.txt

@@ -1,4 +1,5 @@
 #nullable enable
+override Microsoft.Maui.Controls.Platform.Compatibility.ShellFlyoutRenderer.OnLayout(bool changed, int left, int top, int right, int bottom) -> void
 override Microsoft.Maui.Controls.Shapes.Shape.OnPropertyChanged(string? propertyName = null) -> void
 ~override Microsoft.Maui.Controls.Handlers.Items.MauiRecyclerView<TItemsView, TAdapter, TItemsViewSource>.OnInterceptTouchEvent(Android.Views.MotionEvent e) -> bool
 ~override Microsoft.Maui.Controls.Handlers.Items.MauiRecyclerView<TItemsView, TAdapter, TItemsViewSource>.OnTouchEvent(Android.Views.MotionEvent e) -> bool

src/Controls/tests/DeviceTests/Elements/Shell/ShellTests.cs

@@ -1139,6 +1139,32 @@ await CreateHandlerAndAddToWindow<IWindowHandler>(shell, _ =>
 			});
 		}
 
+		[Fact]
+		public async Task SettingFrameDoesTriggerInvalidatedMeasure()
+		{
+			SetupBuilder();
+
+			int measureInvalidatedCount = 0;
+
+			var page = new ContentPage();
+			var shell = await CreateShellAsync(shell =>
+			{
+				shell.CurrentItem = new ShellContent { Content = page };
+			});
+
+			shell.MeasureInvalidated += (s, e) =>
+			{
+				measureInvalidatedCount++;
+			};
+
+			shell.Frame = new Microsoft.Maui.Graphics.Rect(0, 0, 100, 100);
+
+			await CreateHandlerAndAddToWindow<IWindowHandler>(shell, _ =>
+			{
+				Assert.Equal(1, measureInvalidatedCount);
+			});
+		}
+
 		protected Task<Shell> CreateShellAsync(Action<Shell> action) =>
 			InvokeOnMainThreadAsync(() =>
 			{