dotnet 6.0.100-rc.1.21418.40: System.Windows.Extensions types are not supported on this platform

[campersau]

• .NET Core Version: 6.0.100-rc.1.21418.40 / 6.0.0-rc.1.21420.5 / 6.0.0-rc.2.21420.29
• Windows version: Windows 10 21H1 Build 19043.1165
• Does the bug reproduce also in WPF for .NET Framework 4.8?: No
• Is this bug related specifically to tooling in Visual Studio (e.g. XAML Designer, Code editing, etc...)? No

Problem description:
Since dotnet 6.0.100-rc.1.21418.40 we get a System.Windows.Extensions types are not supported on this platform exception when trying to debug and/or publish any WPF app.

Actual behavior:
The following exception is thrown:

System.Windows.Markup.XamlParseException
 HResult=0x80131501
 Nachricht = Zeilennummer "11" und Zeilenposition "7" von "Bei der Initialisierung von "WpfApp3.MainWindow" wurde eine Ausnahme ausgelöst.".
 Quelle = PresentationFramework
 Stapelüberwachung:
  bei System.Windows.Markup.XamlReader.RewrapException(Exception e, IXamlLineInfo lineInfo, Uri baseUri)
  bei System.Windows.Markup.WpfXamlLoader.Load(XamlReader xamlReader, IXamlObjectWriterFactory writerFactory, Boolean skipJournaledProperties, Object rootObject, XamlObjectWriterSettings settings, Uri baseUri)
  bei System.Windows.Markup.WpfXamlLoader.LoadBaml(XamlReader xamlReader, Boolean skipJournaledProperties, Object rootObject, XamlAccessLevel accessLevel, Uri baseUri)
  bei System.Windows.Markup.XamlReader.LoadBaml(Stream stream, ParserContext parserContext, Object parent, Boolean closeStream)
  bei System.Windows.Application.LoadComponent(Object component, Uri resourceLocator)
  bei WpfApp3.MainWindow.InitializeComponent() in C:\Users\d000010\source\repos\WpfApp3\MainWindow.xaml: Zeile1

 Diese Ausnahme wurde ursprünglich von dieser Aufrufliste ausgelöst:
   [Externer Code]

Innere Ausnahme 1:
PlatformNotSupportedException: System.Windows.Extensions types are not supported on this platform.
  bei System.Xaml.Permissions.XamlAccessLevel.AssemblyAccessTo(Assembly assembly)
  bei System.Windows.SystemResources.ResourceDictionaries.LoadDictionary(Assembly assembly, String assemblyName, String resourceName, Boolean isTraceEnabled, Uri& dictionarySourceUri)
  bei System.Windows.SystemResources.ResourceDictionaries.LoadThemedDictionary(Boolean isTraceEnabled)
  bei System.Windows.SystemResources.FindDictionaryResource(Object key, Type typeKey, ResourceKey resourceKey, Boolean isTraceEnabled, Boolean allowDeferredResourceReference, Boolean mustReturnDeferredResourceReference, Boolean& canCache)
  bei System.Windows.SystemResources.FindResourceInternal(Object key, Boolean allowDeferredResourceReference, Boolean mustReturnDeferredResourceReference)
  bei System.Windows.SystemResources.FindThemeStyle(DependencyObjectType key)
  bei System.Windows.StyleHelper.GetThemeStyle(FrameworkElement fe, FrameworkContentElement fce)
  bei System.Windows.FrameworkElement.UpdateThemeStyleProperty()
  bei System.Windows.FrameworkElement.OnInitialized(EventArgs e)
  bei System.Windows.FrameworkElement.TryFireInitialized()
  bei System.Windows.FrameworkElement.EndInit()
  bei MS.Internal.Xaml.Runtime.ClrObjectRuntime.InitializationGuard(XamlType xamlType, Object obj, Boolean begin)

Expected behavior:
No exception.

Minimal repro:

• Install the latest dotnet SDK from https://github.com/dotnet/installer.
• Create a new WPF app in Visual Studio 2022
• Debug it

Reference: NuGetPackageExplorer/NuGetPackageExplorer#1350

[ryalanms]

The incorrect runtime dependency version issue is tracked here: dotnet/sdk#19871.

[singhashish-wpf]

Fixed in WindowsDesktopSDK.

[ryalanms]

Parent issue has been resolved. Closing...