Just trigger SizeChanged when Window size changes

src/Controls/src/Core/Window/Window.cs

@@ -9,6 +9,7 @@
 using Microsoft.Maui.Controls.Internals;
 using Microsoft.Maui.Controls.Platform;
 using Microsoft.Maui.Graphics;
+using Microsoft.Maui.Layouts;
 
 namespace Microsoft.Maui.Controls
 {
@@ -202,60 +203,57 @@ double GetSizeCoordinate(BindableProperty property)
 
 		void IWindow.FrameChanged(Rect frame)
 		{
-			var x = X;
-			var y = Y;
-			var width = Width;
-			var height = Height;
-			if (new Rect(x, y, width, height) == frame)
+			if (new Rect(X, Y, Width, Height) == frame)
 				return;
 
 			_batchFrameUpdate++;
+			bool shouldTriggerSizeChanged = (Width != frame.Width) || (Height != frame.Height);
 
-			SetPropertyChanging(XProperty, nameof(X), x, frame.X);
-			SetPropertyChanging(YProperty, nameof(Y), y, frame.Y);
-			SetPropertyChanging(WidthProperty, nameof(Width), width, frame.Width);
-			SetPropertyChanging(HeightProperty, nameof(Height), height, frame.Height);
-
-			SetValueCore(XProperty, frame.X, SetValueFlags.None, SetValuePrivateFlags.Silent, SetterSpecificity.FromHandler);
-			SetValueCore(YProperty, frame.Y, SetValueFlags.None, SetValuePrivateFlags.Silent, SetterSpecificity.FromHandler);
-			SetValueCore(WidthProperty, frame.Width, SetValueFlags.None, SetValuePrivateFlags.Silent, SetterSpecificity.FromHandler);
-			SetValueCore(HeightProperty, frame.Height, SetValueFlags.None, SetValuePrivateFlags.Silent, SetterSpecificity.FromHandler);
+			X = frame.X;
+			Y = frame.Y;
+			Width = frame.Width;
+			Height = frame.Height;
 
 			_batchFrameUpdate--;
 			if (_batchFrameUpdate < 0)
 				_batchFrameUpdate = 0;
 
-			if (_batchFrameUpdate == 0)
+			if (_batchFrameUpdate == 0 && shouldTriggerSizeChanged)
 			{
-				SetPropertyChanged(XProperty, nameof(X), x, frame.X);
-				SetPropertyChanged(YProperty, nameof(Y), y, frame.Y);
-				SetPropertyChanged(WidthProperty, nameof(Width), width, frame.Width);
-				SetPropertyChanged(HeightProperty, nameof(Height), height, frame.Height);
-
 				SizeChanged?.Invoke(this, EventArgs.Empty);
 			}
 
-			[MethodImpl(MethodImplOptions.AggressiveInlining)]
-			void SetPropertyChanging(BindableProperty property, string name, double oldValue, double newValue)
+
+			// If for some reason during the PropertyChanged event on X,Y,Width,Height
+			// the user has changed these values. Then we need to propagate them back to the handler
+			UpdateHandler(X != frame.X, nameof(X));
+			UpdateHandler(Y != frame.Y, nameof(Y));
+			UpdateHandler(Width != frame.Width, nameof(Width));
+			UpdateHandler(Height != frame.Height, nameof(Height));
+
+
+			void UpdateHandler(bool condition, string property)
 			{
-				if (oldValue == newValue)
+				if (Handler is null || !condition)
+				{
 					return;
+				}
 
-				property.PropertyChanging?.Invoke(this, oldValue, newValue);
-				OnPropertyChanging(name);
+				Handler.UpdateValue(property);
 			}
+		}
 
-			[MethodImpl(MethodImplOptions.AggressiveInlining)]
-			void SetPropertyChanged(BindableProperty property, string name, double oldValue, double newValue)
+		private protected override void UpdateHandlerValue(string property)
+		{
+			if (_batchFrameUpdate > 0 && (property == nameof(X) || property == nameof(Y) || property == nameof(Width) || property == nameof(Height)))
 			{
-				if (oldValue == newValue)
-					return;
-
-				OnPropertyChanged(name);
-				property.PropertyChanged?.Invoke(this, oldValue, newValue);
+				return;
 			}
+
+			base.UpdateHandlerValue(property);
 		}
 
+
 		public event EventHandler<ModalPoppedEventArgs>? ModalPopped;
 		public event EventHandler<ModalPoppingEventArgs>? ModalPopping;
 		public event EventHandler<ModalPushedEventArgs>? ModalPushed;

src/Controls/tests/Core.UnitTests/WindowsTests.cs

@@ -449,6 +449,20 @@ public void SettingCoreFrameOnlyFiresEventOnce()
 			Assert.Equal(new[] { "X", "Y", "Width", "Height" }, changedProperties);
 		}
 
+		[Fact]
+		public void MovingWindowDoNotTriggerSizeChanged()
+		{
+			var sizeChangedCount = 0;
+
+			var window = new TestWindow();
+			window.SizeChanged += (sender, e) => sizeChangedCount++;
+
+			((IWindow)window).FrameChanged(new Rect(100, 200, 300, 400));
+			((IWindow)window).FrameChanged(new Rect(200, 300, 300, 400));
+
+			Assert.Equal(1, sizeChangedCount);
+		}
+
 		[Fact]
 		public void SettingSameCoreFrameDoesNothing()
 		{
@@ -486,7 +500,7 @@ public void UpdatingSingleCoordinateOnlyFiresSinglePropertyAndFrameEvent()
 
 			((IWindow)window).FrameChanged(new Rect(100, 250, 300, 400));
 
-			Assert.Equal(1, sizeChangedCount);
+			Assert.Equal(0, sizeChangedCount);
 			Assert.Equal(new[] { "Y" }, changingProperties);
 			Assert.Equal(new[] { "Y" }, changedProperties);
 		}