diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
index 0bf4a912c..b9e1e2ce1 100644
--- a/.devcontainer/devcontainer.json
+++ b/.devcontainer/devcontainer.json
@@ -1,6 +1,6 @@
 {
   "name": "WPF UI Docs Dev Container",
-  "image": "mcr.microsoft.com/dotnet/sdk:8.0",
+  "image": "mcr.microsoft.com/dotnet/sdk:9.0",
   "features": {
     "ghcr.io/devcontainers/features/node:1": {
       "version": "20"
diff --git a/.github/workflows/top-issues-dashboard.yml b/.github/workflows/top-issues-dashboard.yml
new file mode 100644
index 000000000..f1c3ffbf6
--- /dev/null
+++ b/.github/workflows/top-issues-dashboard.yml
@@ -0,0 +1,24 @@
+name: wpf-ui-top-issues-dashboard
+on:
+  schedule:
+    - cron: '0 0 */1 * *'
+
+jobs:
+  ShowAndLabelTopIssues:
+    name: Display and label top issues.
+    runs-on: ubuntu-latest
+    steps:
+      - name: Top Issues action
+        uses: rickstaa/top-issues-action@v1.3.101
+        env:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          top_list_size: 10
+          label: true
+          dashboard: true
+          dashboard_show_total_reactions: true
+          top_issues: true
+          top_bugs: true
+          top_features: true
+          feature_label: feature
+          top_pull_requests: true
diff --git a/.github/workflows/wpf-ui-cd-docs.yaml b/.github/workflows/wpf-ui-cd-docs.yaml
index f6b39b482..1464f4dc6 100644
--- a/.github/workflows/wpf-ui-cd-docs.yaml
+++ b/.github/workflows/wpf-ui-cd-docs.yaml
@@ -33,10 +33,10 @@ jobs:
         uses: actions/setup-node@v4
         with:
           node-version: 18.x
-      - name: Setup .NET Core SDK 8.x
+      - name: Setup .NET Core SDK 9.x
         uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: 8.x
+          dotnet-version: 9.x
 
       - name: Install docfx
         run: dotnet tool update -g docfx
diff --git a/.github/workflows/wpf-ui-cd-extension.yaml b/.github/workflows/wpf-ui-cd-extension.yaml
index 6bd56b3c9..2635972b5 100644
--- a/.github/workflows/wpf-ui-cd-extension.yaml
+++ b/.github/workflows/wpf-ui-cd-extension.yaml
@@ -4,7 +4,7 @@ on:
   push:
     branches: [main]
     paths:
-      - 'src/Wpf.Ui.Extension**`
+      - 'src/Wpf.Ui.Extension**'
 
   workflow_dispatch:
 
diff --git a/.github/workflows/wpf-ui-cd-nuget.yaml b/.github/workflows/wpf-ui-cd-nuget.yaml
index a49cb274e..f47d13215 100644
--- a/.github/workflows/wpf-ui-cd-nuget.yaml
+++ b/.github/workflows/wpf-ui-cd-nuget.yaml
@@ -3,6 +3,8 @@ name: wpf-ui-cd-nuget
 on:
   push:
     branches: [main]
+    paths:
+      - 'src/**'
 
   workflow_dispatch:
 
@@ -17,10 +19,10 @@ jobs:
       - uses: nuget/setup-nuget@v2
         with:
           nuget-api-key: ${{ secrets.NUGET_API_KEY }}
-      - name: Setup .NET Core SDK 8.x
+      - name: Setup .NET Core SDK 9.x
         uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: 8.x
+          dotnet-version: 9.x
 
       - name: Fetch the certificate
         run: |
diff --git a/.github/workflows/wpf-ui-pr-validator.yaml b/.github/workflows/wpf-ui-pr-validator.yaml
index c2e4fa698..7a641dcac 100644
--- a/.github/workflows/wpf-ui-pr-validator.yaml
+++ b/.github/workflows/wpf-ui-pr-validator.yaml
@@ -17,10 +17,10 @@ jobs:
       - uses: nuget/setup-nuget@v2
         with:
           nuget-api-key: ${{ secrets.NUGET_API_KEY }}
-      - name: Setup .NET Core SDK 8.x
+      - name: Setup .NET Core SDK 9.x
         uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: 8.x
+          dotnet-version: 9.x
 
       - name: Install dependencies
         run: dotnet restore
diff --git a/Directory.Build.props b/Directory.Build.props
index f3160f4fa..cf67c770c 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -6,7 +6,7 @@
   </PropertyGroup>
 
   <PropertyGroup>
-    <Version>4.0.0-rc.2</Version>
+    <Version>4.0.0-rc.3</Version>
     <AssemblyVersion>4.0.0</AssemblyVersion>
   </PropertyGroup>
 
@@ -41,7 +41,7 @@
 
   <PropertyGroup>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
-    <LangVersion>12.0</LangVersion>
+    <LangVersion>13.0</LangVersion>
     <Nullable>enable</Nullable>
 
     <!--
diff --git a/README.md b/README.md
index ce430b6fe..93206830f 100644
--- a/README.md
+++ b/README.md
@@ -29,7 +29,7 @@ Support the development of WPF UI and other innovative projects by becoming a sp
 [Sponsor WPF UI on GitHub](https://github.com/sponsors/lepoco)
 
 ## 🚀 Getting started
-ąś
+
 For a starter guide see our [documentation](https://wpfui.lepo.co/documentation/).
 
 **WPF UI Gallery** is a free application available in the _Microsoft Store_, with which you can test all functionalities.  
diff --git a/docs/documentation/getting-started.md b/docs/documentation/getting-started.md
index c22b1cc85..01576cf0e 100644
--- a/docs/documentation/getting-started.md
+++ b/docs/documentation/getting-started.md
@@ -2,8 +2,7 @@
 
 ## Adding dictionaries
 
-[XAML](https://docs.microsoft.com/en-us/dotnet/desktop/wpf/xaml/?view=netdesktop-6.0), and hence WPF, operate on resource dictionaries. These are HTML-like files that describe the appearance and various aspects of the [controls](https://wpfui.lepo.co/documentation/controls).  
-**WPF UI** adds its own sets of these files to tell the application how the controls should look like.
+[XAML](https://docs.microsoft.com/en-us/dotnet/desktop/wpf/xaml/?view=netdesktop-6.0), and hence WPF, operate on resource dictionaries. These are HTML-like files that describe the appearance and various aspects of the [controls](https://wpfui.lepo.co/documentation/controls). **WPF UI** adds its own sets of these files to tell the application how the controls should look.
 
 There should be a file called `App.xaml` in your new application. Add new dictionaries to it using **WPF UI** `ControlsDictionary` and `ThemesDictionary` classes:
 
@@ -20,16 +19,13 @@ There should be a file called `App.xaml` in your new application. Add new dictio
     </ResourceDictionary>
   </Application.Resources>
 </Application>
-
 ```
 
-You can choose a color theme here,  
-`Light` or `Dark`.
+Notice that the `ThemeDictionary` lets you choose a color theme, `Light` or `Dark`.
 
 ## The main window
 
-There should be a `MainWindow.xaml` file in your newly created application.  
-It contains the arrangement of the controls used and their parameters.
+There should be a `MainWindow.xaml` file in your newly created application. It contains the arrangement of the controls used and their parameters.
 
 ```xml
 <Window x:Class="WpfApp1.MainWindow"
@@ -46,7 +42,7 @@ It contains the arrangement of the controls used and their parameters.
 </Window>
 ```
 
-You can add a new namespace to this window to tell the interpreter that you will be using controls from somewhere, like the **WPF UI** library.
+Add the **WPF UI** library namespace to this window to tell the XAML compiler that you will be using controls from the library.
 
 ```xml
 <Window
@@ -56,7 +52,7 @@ You can add a new namespace to this window to tell the interpreter that you will
 
 ## Adding controls
 
-To add a new control from the **WPF UI** library, you just need to enter its class name, prefixing it with the `ui:` prefix:
+To add a new control from the **WPF UI** library, just enter its class name, prefixing it with the `ui:` prefix:
 
 ```xml
 <Window x:Class="WpfApp1.MainWindow"
@@ -76,5 +72,6 @@ To add a new control from the **WPF UI** library, you just need to enter its cla
 
 # Well...
 
-That's it when it comes to the basics, information about individual controls can be found in [documentation](https://wpfui.lepo.co/documentation/), rules for building a WPF application can be found in the [official Microsoft documentation](https://learn.microsoft.com/en-us/dotnet/desktop/wpf/controls/styles-templates-overview?view=netdesktop-6.0). You can check out [**how to build MVVM applications** here](https://learn.microsoft.com/en-us/windows/communitytoolkit/mvvm/puttingthingstogether).  
-If you think this documentation sucks, [help improve it here](https://github.com/lepoco/wpfui/tree/development/docs/tutorial).
+That's it when it comes to the basics, information about individual controls can be found in [documentation](https://wpfui.lepo.co/documentation/). Rules for building a WPF application can be found in the [official Microsoft documentation](https://learn.microsoft.com/en-us/dotnet/desktop/wpf/controls/styles-templates-overview?view=netdesktop-6.0). You can check out [**how to build MVVM applications** here](https://learn.microsoft.com/en-us/windows/communitytoolkit/mvvm/puttingthingstogether).
+
+If you think this documentation needs improvement, please [help improve it here](https://github.com/lepoco/wpfui/tree/development/docs/tutorial).
diff --git a/docs/documentation/system-theme-watcher.md b/docs/documentation/system-theme-watcher.md
index e69de29bb..c703f7d69 100644
--- a/docs/documentation/system-theme-watcher.md
+++ b/docs/documentation/system-theme-watcher.md
@@ -0,0 +1,88 @@
+# SystemThemeWatcher
+
+SystemThemeWatcher automatically updates the application background if the system theme or color changes. This component is used to adapt the application's background effect and theme according to the system theme.
+
+## Features
+
+  * Automatic Theme Updates: Updates the application's background and theme when the system theme changes.
+
+  * Global Settings: Settings apply globally and cannot be changed for each System.Windows.Window.
+
+  * Supported Backdrop Types: Provides background effects compatible with WindowBackdropType types (e.g., Egg).
+
+
+## Usage
+
+You can use SystemThemeWatcher to start watching a window's background and theme like this:
+
+```cs
+SystemThemeWatcher.Watch(this as System.Windows.Window);
+SystemThemeWatcher.UnWatch(this as System.Windows.Window);
+```
+
+or
+```cs
+SystemThemeWatcher.Watch(
+    _serviceProvider.GetRequiredService<MainWindow>()
+);
+```
+
+## Example Usage
+
+Here's an example of using SystemThemeWatcher in the MainWindow class to start watching the theme when the window is loaded:
+
+```cs
+namespace MyApp;
+
+public partial class MainWindow : Window
+{
+    public MainWindow()
+    {
+        InitializeComponent();
+
+        Loaded += (sender, args) =>
+        {
+            Wpf.Ui.Appearance.SystemThemeWatcher.Watch(
+                this,                                    // Window class
+                Wpf.Ui.Controls.WindowBackdropType.Mica, // Background type
+                true                                     // Whether to change accents automatically
+            );
+        };
+    }
+}
+```
+
+## Methods
+
+### Watch
+
+Applies the background effect and theme according to the system theme to the observed window.
+
+```cs
+public static void Watch(
+    Window? window,
+    WindowBackdropType backdrop = WindowBackdropType.Mica,
+    bool updateAccents = true
+)
+```
+
+### UnWatch
+
+Stops watching the window and removes the hook to receive system messages.
+
+```cs
+public static void UnWatch(Window? window)
+
+```
+
+### WndProc
+
+Listens to system messages on the application windows.
+
+```cs
+private static IntPtr WndProc(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
+
+```
+
+> [!IMPORTANT]
+> If UnWatch is called on a window that has not yet loaded, an InvalidOperationException may occur. Ensure that the window is loaded before calling UnWatch.
diff --git a/src/Wpf.Ui.Abstractions/Wpf.Ui.Abstractions.csproj b/src/Wpf.Ui.Abstractions/Wpf.Ui.Abstractions.csproj
index 23968e634..332b5d0ac 100644
--- a/src/Wpf.Ui.Abstractions/Wpf.Ui.Abstractions.csproj
+++ b/src/Wpf.Ui.Abstractions/Wpf.Ui.Abstractions.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <PackageId>WPF-UI.Abstractions</PackageId>
-    <TargetFrameworks>netstandard2.0;netstandard2.1;net462;net472;net6.0;net8.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;netstandard2.1;net462;net472;net6.0;net8.0;net9.0</TargetFrameworks>
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
     <Description>Abstractions for the WPF UI.</Description>
     <CommonTags>$(CommonTags);abstractions;standard</CommonTags>
diff --git a/src/Wpf.Ui.DependencyInjection/Wpf.Ui.DependencyInjection.csproj b/src/Wpf.Ui.DependencyInjection/Wpf.Ui.DependencyInjection.csproj
index 0ce875cc9..421efb133 100644
--- a/src/Wpf.Ui.DependencyInjection/Wpf.Ui.DependencyInjection.csproj
+++ b/src/Wpf.Ui.DependencyInjection/Wpf.Ui.DependencyInjection.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <PackageId>WPF-UI.DependencyInjection</PackageId>
-    <TargetFrameworks>netstandard2.0;netstandard2.1;net462;net472;net6.0;net8.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;netstandard2.1;net462;net472;net6.0;net8.0;net9.0</TargetFrameworks>
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
     <Description>Dependency injection for the WPF UI.</Description>
     <CommonTags>$(CommonTags);dependency;injection;abstractions;standard</CommonTags>
@@ -24,4 +24,4 @@
     <ProjectReference Include="..\Wpf.Ui.Abstractions\Wpf.Ui.Abstractions.csproj" />
   </ItemGroup>
 
-</Project>
\ No newline at end of file
+</Project>
diff --git a/src/Wpf.Ui.FontMapper/Wpf.Ui.FontMapper.csproj b/src/Wpf.Ui.FontMapper/Wpf.Ui.FontMapper.csproj
index c9595d6dc..4b231cae5 100644
--- a/src/Wpf.Ui.FontMapper/Wpf.Ui.FontMapper.csproj
+++ b/src/Wpf.Ui.FontMapper/Wpf.Ui.FontMapper.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net9.0</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/src/Wpf.Ui.Gallery/Wpf.Ui.Gallery.csproj b/src/Wpf.Ui.Gallery/Wpf.Ui.Gallery.csproj
index 057dbd043..68ecff1ff 100644
--- a/src/Wpf.Ui.Gallery/Wpf.Ui.Gallery.csproj
+++ b/src/Wpf.Ui.Gallery/Wpf.Ui.Gallery.csproj
@@ -3,7 +3,7 @@
   <PropertyGroup>
     <RootNamespace>Wpf.Ui.Gallery</RootNamespace>
     <OutputType>WinExe</OutputType>
-    <TargetFramework>net8.0-windows10.0.22621.0</TargetFramework>
+    <TargetFramework>net9.0-windows10.0.22621.0</TargetFramework>
     <SupportedOSPlatformVersion>10.0.18362.0</SupportedOSPlatformVersion>
     <UseWPF>true</UseWPF>
     <EnableWindowsTargeting>true</EnableWindowsTargeting>
diff --git a/src/Wpf.Ui.SyntaxHighlight/Wpf.Ui.SyntaxHighlight.csproj b/src/Wpf.Ui.SyntaxHighlight/Wpf.Ui.SyntaxHighlight.csproj
index 34d37ceca..0b7080a5f 100644
--- a/src/Wpf.Ui.SyntaxHighlight/Wpf.Ui.SyntaxHighlight.csproj
+++ b/src/Wpf.Ui.SyntaxHighlight/Wpf.Ui.SyntaxHighlight.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <PackageId>WPF-UI.SyntaxHighlight</PackageId>
-    <TargetFrameworks>net462;net472;net481;net6.0-windows;net8.0-windows</TargetFrameworks>
+    <TargetFrameworks>net462;net472;net481;net6.0-windows;net8.0-windows;net9.0-windows</TargetFrameworks>
     <Description>Native tast notification support for WPF using the WPF UI library.</Description>
     <CommonTags>$(CommonTags);syntax;highlight</CommonTags>
     <UseWPF>true</UseWPF>
diff --git a/src/Wpf.Ui.ToastNotifications/Wpf.Ui.ToastNotifications.csproj b/src/Wpf.Ui.ToastNotifications/Wpf.Ui.ToastNotifications.csproj
index 5b060fec9..0d5648e1b 100644
--- a/src/Wpf.Ui.ToastNotifications/Wpf.Ui.ToastNotifications.csproj
+++ b/src/Wpf.Ui.ToastNotifications/Wpf.Ui.ToastNotifications.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <PackageId>WPF-UI.ToastNotifications</PackageId>
-    <TargetFrameworks>net462;net472;net481;net6.0-windows;net8.0-windows</TargetFrameworks>
+    <TargetFrameworks>net462;net472;net481;net6.0-windows;net8.0-windows;net9.0-windows</TargetFrameworks>
     <Description>Native tast notification support for WPF using the WPF UI library.</Description>
     <CommonTags>$(CommonTags);toast;notifications</CommonTags>
     <UseWPF>true</UseWPF>
diff --git a/src/Wpf.Ui.Tray/Wpf.Ui.Tray.csproj b/src/Wpf.Ui.Tray/Wpf.Ui.Tray.csproj
index 5a07bb940..b06f1e6d5 100644
--- a/src/Wpf.Ui.Tray/Wpf.Ui.Tray.csproj
+++ b/src/Wpf.Ui.Tray/Wpf.Ui.Tray.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <PackageId>WPF-UI.Tray</PackageId>
-    <TargetFrameworks>net462;net472;net481;net6.0-windows;net8.0-windows</TargetFrameworks>
+    <TargetFrameworks>net462;net472;net481;net6.0-windows;net8.0-windows;net9.0-windows</TargetFrameworks>
     <Description>Native tray menu icon support for WPF using the WPF UI library.</Description>
     <CommonTags>$(CommonTags);tray;notifyicon;notify</CommonTags>
     <UseWPF>true</UseWPF>
diff --git a/src/Wpf.Ui/Controls/MessageBox/MessageBox.cs b/src/Wpf.Ui/Controls/MessageBox/MessageBox.cs
index 0e37bcb1e..1da1681f2 100644
--- a/src/Wpf.Ui/Controls/MessageBox/MessageBox.cs
+++ b/src/Wpf.Ui/Controls/MessageBox/MessageBox.cs
@@ -236,10 +236,12 @@ public bool IsPrimaryButtonEnabled
     /// </summary>
     public IRelayCommand TemplateButtonCommand => (IRelayCommand)GetValue(TemplateButtonCommandProperty);
 
+#if !NET8_0_OR_GREATER
     private static readonly PropertyInfo CanCenterOverWPFOwnerPropertyInfo = typeof(Window).GetProperty(
         "CanCenterOverWPFOwner",
         BindingFlags.NonPublic | BindingFlags.Instance
     )!;
+#endif
 
     /// <summary>
     /// Initializes a new instance of the <see cref="MessageBox"/> class.
diff --git a/src/Wpf.Ui/Controls/NavigationView/NavigationViewContentPresenter.cs b/src/Wpf.Ui/Controls/NavigationView/NavigationViewContentPresenter.cs
index 66817641e..23595cfaf 100644
--- a/src/Wpf.Ui/Controls/NavigationView/NavigationViewContentPresenter.cs
+++ b/src/Wpf.Ui/Controls/NavigationView/NavigationViewContentPresenter.cs
@@ -140,11 +140,23 @@ protected override void OnMouseDown(MouseButtonEventArgs e)
         if (e.ChangedButton is MouseButton.XButton1 or MouseButton.XButton2)
         {
             e.Handled = true;
+            return;
         }
 
         base.OnMouseDown(e);
     }
 
+    protected override void OnPreviewKeyDown(KeyEventArgs e)
+    {
+        if (e.Key == Key.F5)
+        {
+            e.Handled = true;
+            return;
+        }
+
+        base.OnPreviewKeyDown(e);
+    }
+
     protected virtual void OnNavigating(System.Windows.Navigation.NavigatingCancelEventArgs eventArgs)
     {
         NotifyContentAboutNavigatingTo(eventArgs.Content);
diff --git a/src/Wpf.Ui/Wpf.Ui.csproj b/src/Wpf.Ui/Wpf.Ui.csproj
index 5e7b139d2..ad0903130 100644
--- a/src/Wpf.Ui/Wpf.Ui.csproj
+++ b/src/Wpf.Ui/Wpf.Ui.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <PackageId>WPF-UI</PackageId>
-    <TargetFrameworks>net462;net472;net481;net6.0-windows;net8.0-windows</TargetFrameworks>
+    <TargetFrameworks>net462;net472;net481;net6.0-windows;net8.0-windows;net9.0-windows</TargetFrameworks>
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
     <Description>WPF UI provides the Fluent experience in your known and loved WPF framework. Intuitive design, themes, navigation and new immersive controls. All natively and effortlessly.</Description>
     <UseWPF>true</UseWPF>
diff --git a/tests/Wpf.Ui.Gallery.UnitTests/Wpf.Ui.Gallery.UnitTests.csproj b/tests/Wpf.Ui.Gallery.UnitTests/Wpf.Ui.Gallery.UnitTests.csproj
index 91abfb142..d0047db9f 100644
--- a/tests/Wpf.Ui.Gallery.UnitTests/Wpf.Ui.Gallery.UnitTests.csproj
+++ b/tests/Wpf.Ui.Gallery.UnitTests/Wpf.Ui.Gallery.UnitTests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net8.0-windows10.0.22621.0</TargetFramework>
+    <TargetFramework>net9.0-windows10.0.22621.0</TargetFramework>
     <IsPackable>false</IsPackable>
   </PropertyGroup>
 
diff --git a/tests/Wpf.Ui.UnitTests/Wpf.Ui.UnitTests.csproj b/tests/Wpf.Ui.UnitTests/Wpf.Ui.UnitTests.csproj
index 26408624f..c2e06abd5 100644
--- a/tests/Wpf.Ui.UnitTests/Wpf.Ui.UnitTests.csproj
+++ b/tests/Wpf.Ui.UnitTests/Wpf.Ui.UnitTests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net7.0-windows</TargetFramework>
+    <TargetFramework>net9.0-windows</TargetFramework>
     <IsPackable>false</IsPackable>
   </PropertyGroup>