/// <summary>
/// Sets the application user model id for the window.
/// </summary>
/// <param name="hwnd">The window.</param>
/// <param name="appId">The application id to set.</param>
public static void SetWindowAppId(IntPtr hwnd, string appId)
{
var iPropertyStoreGuid = new Guid("886D8EEB-8CF2-4446-8D02-CDBA1DBDCF99");
SHGetPropertyStoreForWindow(hwnd, ref iPropertyStoreGuid, out IPropertyStore propertyStore);
var appid = new PROPVARIANT(appId);
propertyStore.SetValue(ref PropertyKey.SystemAppUserModelIDPropertyKey, appid);
PROPVARIANT.ClearProp(appid);
}