Accent color is not overridable by setting SystemAccentColor or ColorPaletteResources

Describe the bug

The accent color seems to be fixed/readonly/hardcoded in WinAppSDK 1.0 / WinUI 3.0. It is not overridable by the usual techniques.

Steps to reproduce the bug

• Create a WinAppSDK 1.0 WAP project
• Replace the Ressources in App.xaml with:

<Application.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <XamlControlsResources xmlns="using:Microsoft.UI.Xaml.Controls" />
            <ColorPaletteResources Accent="Blue" />
        </ResourceDictionary.MergedDictionaries>
        
        <Color x:Key="SystemAccentColor">Red</Color>

        <ResourceDictionary.ThemeDictionaries>
            <ResourceDictionary x:Key="Dark">
                <Color x:Key="SystemAccentColor">Green</Color>
            </ResourceDictionary>
            <ResourceDictionary x:Key="Light">
                <Color x:Key="SystemAccentColor">Magenta</Color>
            </ResourceDictionary>
        </ResourceDictionary.ThemeDictionaries>
    </ResourceDictionary>
</Application.Resources>

• Replace the Content of MainWindow.xaml with:

 <Grid Background="DarkGray" RequestedTheme="Dark">
        <ToggleButton HorizontalAlignment="Center" VerticalAlignment="Center" x:Name="myButton" IsChecked="True">Click Me</ToggleButton>
</Grid>

Expected behavior

• It would be nice if at least one of the methods of overriding the accent color would work.
• It seems like the official Windows App SDK documentation tells us lies (Overriding the accent color)!?

Screenshots

• As you can see, my system’s accent color is used, and none of my overrides from App.xaml work:

NuGet package version

WinUI 3 - Windows App SDK 1.0 (If you’re seeing your issue in older previews of WinUI 3, please try this release)

Windows app type

• UWP
• Win32

Device form factor

Desktop

Windows version

Insider Build (xxxxx)

Additional context

Tested on Windows 11 Insider Build 22504.1010

[WelterDevelopment]

It seems that ColorpaletteResource does nothing to the new WinUI 3.0 controls. Normally it should calculate all shades of SystemAccentColor automatically. And setting SystemAccentColor does nothing because the new WinUI 3.0 AccentBrushes seem to be based on:

• SystemAccentColorLight2 in Dark Mode and
• SystemAccentColorDark1 in Light Mode

So I found my workaround to be:

• Declare SystemAccentColorLight2 and SystemAccentColorDark1 in App.xaml
• Update the Accent color at Runtime via c# with
  • Application.Current.Resources["SystemAccentColorLight2"] = SomeLightColor;
  • Application.Current.Resources["SystemAccentColorDark1"] = SomeDarkColor;
• The very ugly workaround “ReloadPageTheme” (Using ColorPaletteResources in code-behind) seems to be still necessary in WinAppSDK 1.0 / WinUI 3.0

[Jhngrntn]

If using WinUI 3, I found it was important to call it a “Color” rather than “SolidColorBrush”. Otherwise, it won’t work.

<Color x:Key="SystemAccentColorLight1">#aeb5f2</Color> <Color x:Key="SystemAccentColorLight2">#8993ec</Color> <Color x:Key="SystemAccentColorLight3">#6571e6</Color>