In WPF the WindowsFormsHost control is displayed on top of the Backstage menu Reason for declining: The WindowsFormsHost element is drawn on top of any Adorner elements. As the RadRibbonBackstage is an Adorner the WindowsFormsHost is drawn on top of it. As a workaround to this framework limitation you could bind Visibility of the WindowsFormsHost to the IsBackstageOpen property of the RadRibbonView and collapse/hide it when the backstage is open. You can find more information about the WindowsFormsHost and its features and limitation in this article ( http://msdn.microsoft.com/en-us/library/ms744952.aspx ).
When maximized (or when dragged from maximized), RadRibbonWindow ,might not render it's chrome. Reproducable on Windows 7, 64bit machine.