WPF window inside an MFC window not shown
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I know this is kind of a long shot, but maybe someone has an idea.

I have a wpf window inside mfc window. 
The system I am working on contains our own keyboard buttons.
When I press a button that fires an event that usually just opens an MFC window, then the MFC window opens, but for some reason pressing another button which is supposed to open the WPF window doesn't work. I can see the mfc window, but not the WPF one which is supposed to be inside it.
With snoop I can see that the Visibility of the WPF window is Visible, even when the window is not shown. It should also be noted that when I press the first button (to show the MFC window) then the visibility property of the WPF window is stuck on visible (can't change it not with snoop, nor with VS2010), even though it is not shown yet.

When I press any other keyboard button then the WPF window is shown (inside the MFC window).

Any ideas?

Thanks!