perf: Improve Control focus performance

src/Uno.UI/UI/Xaml/Controls/Control/Control.wasm.cs

@@ -11,6 +11,7 @@
 using Uno.Disposables;
 using Uno.UI;
 using View = Microsoft.UI.Xaml.UIElement;
+using Uno.UI.Xaml;
 
 namespace Microsoft.UI.Xaml.Controls
 {
@@ -49,7 +50,7 @@ partial void OnIsFocusableChanged()
 		{
 			var isFocusable = IsFocusable && !IsDelegatingFocusToTemplateChild();
 
-			SetAttribute("tabindex", isFocusable ? "0" : "-1");
+			WindowManagerInterop.SetIsFocusable(HtmlId, isFocusable);
 		}
 
 		private protected virtual bool IsDelegatingFocusToTemplateChild() => false;

src/Uno.UI/UI/Xaml/Window/WindowManagerInterop.wasm.cs

@@ -1051,6 +1051,8 @@ internal static void WindowActivate()
 
 		internal static bool GetIsOverflowing(IntPtr htmlId)
 			=> NativeMethods.GetIsOverflowing(htmlId);
+		internal static void SetIsFocusable(IntPtr htmlId, bool isFocusable)
+			=> NativeMethods.SetIsFocusable(htmlId, isFocusable);
 
 		#region Pointers
 		[Flags]
@@ -1177,6 +1179,9 @@ internal static partial void ArrangeElement(
 
 			[JSImport("globalThis.Uno.UI.WindowManager.current.getIsOverflowing")]
 			internal static partial bool GetIsOverflowing(IntPtr htmlId);
+
+			[JSImport("globalThis.Uno.UI.WindowManager.current.setIsFocusable")]
+			internal static partial void SetIsFocusable(nint htmlId, bool isFocusable);
 		}
 	}
 }

src/Uno.UI/ts/WindowManager.ts

@@ -1790,6 +1790,12 @@ namespace Uno.UI {
 
 			return element.clientWidth < element.scrollWidth || element.clientHeight < element.scrollHeight;
 		}
+
+		public setIsFocusable(elementId: number, isFocusable: boolean) {
+			const element = this.getView(elementId) as HTMLElement;
+
+			element.setAttribute("tabindex", isFocusable ? "0" : "-1");
+		}
 	}
 
 	if (typeof define === "function") {