The basic idea behind the code is the DragCue
to be the sender itself (sender = PartContainer
= a UserControl).
So the user sees the UserControl being dragged to the choosen destination.
If I set DragCue like this it works BUT not as desired:
(shows a yellow rectangle with yellow Fill)
The wanted version (which used to work) is:
e.Options.DragCue = (PartContainer)sender;
(it should show the actual visuals of the UserControl being dragged)
Thanks for your help!