Troubles with SwitchPanel and Windows Form interop

I'm honestly not sure why that would happen.  WPF / WinForms interop in general is sometimes somewhat flakey.  There's the common airspace issue (WinForms content is always above WPF content in the same Window), issues with focus tracking between the platform, etc.  I'm not sure I would recommend using interop controls like WinForms controls in animated areas of your app.

I wonder if you could call InvalidateVisual() or InvalidateMeasure() after this happens to force the WindowsFormsHost to redraw.  But based on what you said with it staying where it was, it sounds like that might not help since it seems like there is a positional issue.  By the fact that you say that it corrects iteself following the mouse over, it seems like we have passed the correct info but WPF just didn't reposition it properly.

I have thougth to something like that, but I don't know what event to track for the positionning. I am not deep in WPF so I need a bit help. Since the WindowsFormsHost is inside a UIElement, I thought I could subscribe to a Parent event, but I am not sure which one to choose that would be fired on repositionning / resizing.

However, I doubt it would work, since sometimes it works without it, and sometimes not... 

You might need to inherit the Panel doing the arranging and override the ArrangeCore method to put your logic there.  That or possibly handle the item's LayoutUpdated event.  I haven't really tried using that event before but I believe it fires on the item after it is arranged.

Allright, I'll try sothming like that and I'll let you know about it. Thank you.