Taskbar Color Reverts When Changing Color Using SetWindowCompositionAttribute in WinUI3

Question

Hi, I am encountering an issue with the taskbar color on Windows. When I change the taskbar color using the SetWindowCompositionAttribute method, the color initially changes as expected. However, as soon as I click the 'Start' button, the taskbar color reverts to the default color specified by the Windows settings.

Steps to Reproduce:

1. Change the taskbar color using SetWindowCompositionAttribute.
2. Observe the taskbar color change.
3. Click the 'Start' button.
4. Notice the taskbar color reverting to the Windows default color.

Expected Behavior: The taskbar color should remain as set by SetWindowCompositionAttribute, even after interacting with the 'Start' button.

Actual Behavior: The taskbar color reverts to the default Windows settings when the 'Start' button is clicked.

Code Sample:

public static void SetTaskbarColor(Color color)
{
    var accentPolicy = default(User32Interop.AccentPolicy);

    accentPolicy.Color = color.ToAbgr();
    accentPolicy.AccentState = 2;
    accentPolicy.Flags = 2;

    var data = default(User32Interop.Windowcompositionattribdata);

    data.Attribute = User32Interop.WindowCompositionAttribute.WcaAccentPolicy;
    data.SizeOfData = Marshal.SizeOf(typeof(User32Interop.AccentPolicy));
    data.Data = Marshal.AllocHGlobal(data.SizeOfData);

    Marshal.StructureToPtr(accentPolicy, data.Data, false);

    var taskbarHandle = User32Interop.FindWindow("Shell_TrayWnd", null);

    var secondaryTaskbarHandle = User32Interop.FindWindow("Shell_SecondaryTrayWnd", null);

    if (taskbarHandle != nint.Zero)
    {
        User32Interop.SetWindowCompositionAttribute(taskbarHandle, ref data);
    }

    if (secondaryTaskbarHandle != nint.Zero)
    {
        User32Interop.SetWindowCompositionAttribute(secondaryTaskbarHandle, ref data);
    }

    Marshal.FreeHGlobal(data.Data);
}

Answer 1

Apps which do this call it in a Thread or a Timer to refresh it

(like for example : https://github.com/WorkingRobot/WallpaperVisualizer/blob/9ccd923ca4379d6f4b1dc40755267ca7e85ae25c/WallpaperVisualizer/WallpaperVisualizer.cs#L53)