Hi,
I tested your Window, and I remove all BMP and event handlers which I do not have the code. The XAML layout can work fine. Please test my code in your side: https://skydrive.live.com/?cid=51b2fdd068799d15#cid=51B2FDD068799D15&id=51B2FDD068799D15%21906
And I guess your behind code may make the control cannot be dragged. How about yourContentRendered="OnContentRendered" event handler of the Window element?
Sincerely,
Bob Bao [MSFT]
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