New Post: AvalongDock - LayoutAnchorable - AutoHide issue

LayoutAnchorable has a Autohide button in the upper right corner.When I click the button,the title hang on one side of the window.When the mouse cover the title, it will show the LayoutAnchorable's content.
But if I set the AllowsTransparency of window to True and WindowStyle to None,I cannot see the LayoutAnchorable's content when the mouse cover the title.Why?How to figure it out?