fix: ThemeResource bindings are not scope-updated on Style switch

src/Uno.UI.RuntimeTests/Tests/Windows_UI_Xaml/Controls/When_ThemeResource_Style_Switch_Page.xaml

@@ -0,0 +1,28 @@
+<UserControl x:Class="Uno.UI.RuntimeTests.When_ThemeResource_Style_Switch_Page"
+			 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+			 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+			 xmlns:local="using:Uno.UI.RuntimeTests.Tests.Windows_UI_Xaml.Controls"
+			 xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+			 xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+			 mc:Ignorable="d"
+			 d:DesignHeight="300"
+			 d:DesignWidth="400">
+
+	<UserControl.Resources>
+		<Style x:Key="FirstButtonStyle" TargetType="Button">
+			<Setter Property="Background" Value="{ThemeResource ButtonBackground}" />
+		</Style>
+		<Style x:Key="SecondButtonStyle" TargetType="Button">
+			<Setter Property="Background" Value="{ThemeResource ButtonBackgroundPressed}" />
+		</Style>
+	</UserControl.Resources>
+	<StackPanel>
+		<Border>
+			<Border.Resources>
+				<SolidColorBrush x:Key="ButtonBackground" Color="Blue" />
+				<SolidColorBrush x:Key="ButtonBackgroundPressed" Color="Red" />
+			</Border.Resources>
+			<Button x:Name="TestBtn" Style="{StaticResource FirstButtonStyle}" Width="100" Height="100" />
+		</Border>
+	</StackPanel>
+</UserControl>

src/Uno.UI.RuntimeTests/Tests/Windows_UI_Xaml/Controls/When_ThemeResource_Style_Switch_Page.xaml.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Runtime.InteropServices.WindowsRuntime;
+using Windows.Foundation;
+using Windows.Foundation.Collections;
+using Windows.UI.Xaml;
+using Windows.UI.Xaml.Controls;
+using Windows.UI.Xaml.Controls.Primitives;
+using Windows.UI.Xaml.Data;
+using Windows.UI.Xaml.Input;
+using Windows.UI.Xaml.Media;
+using Windows.UI.Xaml.Navigation;
+
+namespace Uno.UI.RuntimeTests;
+
+public sealed partial class When_ThemeResource_Style_Switch_Page : UserControl
+{
+	public When_ThemeResource_Style_Switch_Page()
+	{
+		this.InitializeComponent();
+	}
+
+	public Button TestButton => TestBtn;
+}

src/Uno.UI.RuntimeTests/Tests/Windows_UI_Xaml/Given_ThemeResource.cs

@@ -136,6 +136,29 @@ public async Task When_AppLevel_Resource_SplitButton_Override()
 			}
 		}
 
+		[TestMethod]
+		public async Task When_ThemeResource_Style_Switch()
+		{
+			using (StyleHelper.UseFluentStyles())
+			{
+				var SUT = new When_ThemeResource_Style_Switch_Page();
+				WindowHelper.WindowContent = SUT;
+				await WindowHelper.WaitForLoaded(SUT);
+
+				var color = ((SolidColorBrush)SUT.TestButton.Background).Color;
+
+				Assert.AreEqual(Colors.Blue, color);
+
+				SUT.TestButton.Style = (Style)SUT.Resources["SecondButtonStyle"];
+
+				await WindowHelper.WaitForIdle();
+
+				color = ((SolidColorBrush)SUT.TestButton.Background).Color;
+
+				Assert.AreEqual(Colors.Red, color);
+			}
+		}
+
 		private async Task When_DefaultForeground(Color lightThemeColor, Color darkThemeColor)
 		{
 			var run = new Run()

src/Uno.UI/UI/Xaml/Style/Style.cs

@@ -4,8 +4,6 @@
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Linq;
-
-using Uno.Extensions;
 using Uno.Foundation.Logging;
 using Uno.UI;
 using Windows.UI.Xaml.Data;
@@ -73,7 +71,7 @@ internal void ApplyTo(DependencyObject o, DependencyPropertyValuePrecedences pre
 				return;
 			}
 
-			var localPrecedenceDisposable = DependencyObjectExtensions.OverrideLocalPrecedence(o, precedence);
+			IDisposable? localPrecedenceDisposable = null;
 
 			EnsureSetterMap();
 
@@ -82,6 +80,7 @@ internal void ApplyTo(DependencyObject o, DependencyPropertyValuePrecedences pre
 #endif
 			{
 				ResourceResolver.PushNewScope(_xamlScope);
+				localPrecedenceDisposable = DependencyObjectExtensions.OverrideLocalPrecedence(o, precedence);
 
 				if (_flattenedSetters != null)
 				{
@@ -91,15 +90,18 @@ internal void ApplyTo(DependencyObject o, DependencyPropertyValuePrecedences pre
 					}
 				}
 
+				localPrecedenceDisposable?.Dispose();
+				localPrecedenceDisposable = null;
+
 				// Check tree for resource binding values, since some Setters may have set ThemeResource-backed values
-				(o as IDependencyObjectStoreProvider)!.Store.UpdateResourceBindings(ResourceUpdateReason.StaticResourceLoading);
+				(o as IDependencyObjectStoreProvider)!.Store.UpdateResourceBindings(ResourceUpdateReason.ResolvedOnLoading);
 			}
 #if !HAS_EXPENSIVE_TRYFINALLY
 			finally
 #endif
 			{
-				ResourceResolver.PopScope();
 				localPrecedenceDisposable?.Dispose();
+				ResourceResolver.PopScope();
 			}
 		}