TabViewItemHeaderBackground is broken on scale factors > 100%

[WelterDevelopment]

Describe the bug

On Windows 11 and with a WinAppSDK 1.0 WAP project, the standard TabViewItemHeaderBackground at display scale factors > 100% seems to be replaced by an ugly LinearGradientBrush.

Steps to reproduce the bug

• Create a WinAppSDK 1.0 packaged (WAP) desktop app
• Replace the Stackpanel of MainWindow.xaml with:

<Grid Background="DarkGray">
    <TabView HorizontalAlignment="Stretch" VerticalAlignment="Stretch" >
        <TabView.TabItems>
            <TabViewItem Header="Some TabItem">
                <Button x:Name="myButton" Click="myButton_Click">Click Me</Button>
            </TabViewItem>
            <TabViewItem Header="Some other TabItem">
            </TabViewItem>
        </TabView.TabItems>
    </TabView>
</Grid>

• Deploy and start the App with the display scale factor 125% (or anything other than 100%):

:

Expected behavior

• All Brushes should look the same at any scale factor. However, at scale factors > 100%, the standard TabViewItemHeaderBackground seems to be replaced with a LinearGradientBrush
• At 100%, the app looks as expected:

Screenshots

No response

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 10.0.22000 and on the latest insider build.

Is this issue related to microsoft-ui-xaml or to WindowsAppSDK?

[WelterDevelopment]

I Just saw that this is basically a dublicate of #6194