WPF: RibbonWindow is not being collected because of CommandManager

According to RegGa开发者_如何学Cte's memory profiler, my RibbonWindowis not being collected because CommandManager is holding a reference to us. Does this make sense and what can I do about it?

EDIT: This appears to be specific to a RibbonWindow from Microsoft CTP. But still I would like to know why it happens.