chore(calendar): Apply MS reviews

src/Uno.UI/DirectUI/BuildTreeService.cs

@@ -0,0 +1,35 @@
+using System;
+using System.Linq;
+using Windows.UI.Core;
+
+namespace DirectUI
+{
+	internal class BuildTreeService
+	{
+		public void RegisterWork(ITreeBuilder treeBuilder)
+		{
+			treeBuilder.IsRegisteredForCallbacks = true;
+			CoreDispatcher.Main.RunAsync(CoreDispatcherPriority.High, () =>
+			{
+				if (treeBuilder.IsBuildTreeSuspended)
+				{
+					RegisterWork(treeBuilder);
+					return;
+				}
+
+				treeBuilder.IsRegisteredForCallbacks = false;
+
+				var workerHasWorkLeft = treeBuilder.BuildTree();
+
+				if (workerHasWorkLeft)
+				{
+					var workerReRegistered = treeBuilder.IsRegisteredForCallbacks;
+					if (!workerReRegistered)
+					{
+						RegisterWork(treeBuilder);
+					}
+				}
+			});
+		}
+	}
+}

src/Uno.UI/DirectUI/DXamlCore.cs

@@ -2,7 +2,6 @@
 using System.Collections.Generic;
 using System.Text;
 using Windows.ApplicationModel.Resources;
-using Windows.UI.Core;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
 
@@ -18,6 +17,10 @@ internal class DXamlCore
 		public static DXamlCore GetCurrent()
 			=> _current ??= new DXamlCore();
 
+		// UNO: This should **NOT** create the singleton!
+		//		_but_ if we do return a 'null' the 'OnApplyTemplate' of the `CalendarView` will fail.
+		//		As for now our implementation of the 'DXamlCore' is pretty light and stored as a basic singleton,
+		//		we accept to create it even with the "NoCreate" overload.
 		public static DXamlCore GetCurrentNoCreate()
 			=> _current ??= new DXamlCore();
 
@@ -36,42 +39,4 @@ public BuildTreeService GetBuildTreeService()
 		public BudgetManager GetBudgetManager()
 			=> _budgetManager ??= new BudgetManager();
 	}
-
-	internal class BuildTreeService
-	{
-		public void RegisterWork(ITreeBuilder treeBuilder)
-		{
-			treeBuilder.IsRegisteredForCallbacks = true;
-			CoreDispatcher.Main.RunAsync(CoreDispatcherPriority.High, () =>
-			{
-				if (treeBuilder.IsBuildTreeSuspended)
-				{
-					RegisterWork(treeBuilder);
-					return;
-				}
-
-				treeBuilder.IsRegisteredForCallbacks = false;
-
-				var workerHasWorkLeft = treeBuilder.BuildTree();
-
-				if (workerHasWorkLeft)
-				{
-					var workerReRegistered = treeBuilder.IsRegisteredForCallbacks;
-					if (!workerReRegistered)
-					{
-						RegisterWork(treeBuilder);
-					}
-				}
-			});
-		}
-	}
-
-	internal interface ITreeBuilder
-	{
-		public bool IsBuildTreeSuspended { get; }
-
-		public bool IsRegisteredForCallbacks { get; set; }
-
-		public bool BuildTree();
-	}
 }

src/Uno.UI/DirectUI/FocusRect/focusrectoptions.h.cs

@@ -23,7 +23,11 @@ internal struct FocusRectangleOptions
 		// Used to indicate whether this is a continuous focus rectangle (not dashed)
 		// When true, the second rect is drawn inside the first
 		// When false, the rects are drawn as alternating dotted lines
-		public bool isContinuous;
+		//
+		// IMPORTANT UNO: MS recommends to not support dashed focus visual! Only "high visibility focus rects"
+		// (solid lines that are thicker and have two colors to show up on any background/theme).
+		//
+		// public bool isContinuous;
 
 		// Used to indicate if we are drawing a borderless reveal glow
 		public bool isRevealBorderless;

src/Uno.UI/DirectUI/ITreeBuilder.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Linq;
+
+namespace DirectUI
+{
+	internal interface ITreeBuilder
+	{
+		public bool IsBuildTreeSuspended { get; }
+
+		public bool IsRegisteredForCallbacks { get; set; }
+
+		public bool BuildTree();
+	}
+}

src/Uno.UI/DirectUI/JoltCollections.h.cs

@@ -5,6 +5,7 @@
 using System.Collections;
 using System.Collections.Generic;
 using Windows.Foundation.Collections;
+using Windows.System;
 using Windows.UI.Core;
 
 namespace DirectUI
@@ -21,7 +22,7 @@ internal abstract class IteratorBase<T> : IEnumerator<T>
 		//END_INTERFACE_MAP(IteratorBase, ctl.WeakReferenceSource)
 
 		// UNO only
-		protected void CheckThread() => CoreDispatcher.CheckThreadAccess();
+		protected void CheckThread() => DispatcherQueue.CheckThreadAccess();
 
 		public void SetView(IVectorView<T> pView)
 		{

src/Uno.UI/UI/Xaml/Input/FocusManager.cs

@@ -206,9 +206,10 @@ void OnGotFocus()
 		public static event EventHandler<FocusManagerGotFocusEventArgs> GotFocus;
 		public static event EventHandler<FocusManagerLostFocusEventArgs> LostFocus;
 
-		internal static void SetEngagedControl(Control spScrollViewer)
+		internal static void SetEngagedControl(Control control)
 		{
-			// UNO-TODO
+			// Focus engagement applies only to gamepads
+			// We don't support them yet with Uno.
 		}
 	}
 }

src/Uno.UWP/System/DispatcherQueue.cs

@@ -32,6 +32,21 @@ public static DispatcherQueue GetForCurrentThread()
 
 			return _current;
 		}
+
+		/// <summary>
+		/// Enforce access on the UI thread.
+		/// </summary>
+		internal static void CheckThreadAccess()
+		{
+#if !__WASM__
+			// This check is disabled on WASM until threading support is enabled, since HasThreadAccess is currently user-configured (and defaults to false).
+			if (!CoreDispatcher.Main.HasThreadAccess)
+			{
+				throw new InvalidOperationException("The application called an interface that was marshalled for a different thread.");
+			}
+#endif
+		}
+
 #if !HAS_UNO_WINUI
 		public bool TryEnqueue(DispatcherQueueHandler callback)
 		{