### .NET version .NET 9.0.100-rc.2.24453.35 ### Did it work in .NET Framework? No ### Did it work in any of the earlier releases of .NET Core or .NET 5+? This is a new feature Dark Mode: https://github.com/dotnet/winforms/pull/11857 ### Issue description The toolstripPanel have the wrong BackColor that black color in dark mode in DemoConsole application.  ### Steps to reproduce 1. Clone the [DemoConsole](https://github.com/dotnet/winforms/tree/main/src/System.Windows.Forms/tests/IntegrationTests/DesignSurface/DemoConsole) in Winforms repo 2. Enable Dark mode by adding below code lines in the Program.cs file under DemoConsole project ``` #pragma warning disable WFO5001 Application.SetColorMode(SystemColorMode.Dark); ``` 3. Build and run the DemoConsole project, then tab to Align control by hand page. 4. Observe the BackColor of toolstripPanel in dark mode in DemoConsole application