RibbonWindow not working correctly with ThemeMode="System"

[dha125]

Description

RibbonWindow fails to correctly render if ThemeMode="System" is in either App.xaml or MainWindow.xaml. RibbonWindow and Ribbon are well written but seem to have missed the modernization in dotnet 9.

Reproduction Steps

Any valid RibbonWindow fails to render the quick access toolbar in the window title bar in a net9.0-windows or net10.0-windows project if any ThemeMode is set. I'm currently testing with 10.0.100-preview.2.25164.34.

<RibbonWindow x:Class="WpfRibbonApp.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WpfRibbonApp"
mc:Ignorable="d"
Title="MainWindow" Height="450" Width="800"
ThemeMode="System">

Expected behavior

Quick access toolbar in the window title bar.

Actual behavior

See image in expected behavior.

Regression?

No response

Known Workarounds

No response

Impact

No response

Configuration

No response

Other information

No response

[dipeshmsft]

@dha125, the actual issue here is that Ribbon and associated controls are not styled according to Fluent. Currently we have the styles for controls in PresentationFramework assembly.

[dha125]

Thanks for the feedback. Will the Ribbon be modernized for the final dotnet 10 release?