I am developing my own designer and got stuck at a point where I need to establish or implement some business logic whenever any UI Element is dragged and determine if that falls withing the boundaries of another parent control (specifically TabControl or GroupBox), so that the next time we drag the parent, the child moves with it (and of course, in case of TabControl, the child becomes part of the selected TabItem only and the other TabItems would still be shown with empty content). I also want to implement the reverse behaviour, that is, whenever a child is dragged outside the boundaries of a parent control and kept anywhere on the screen.
VisualTreeHelper.HitTest() but that didn't work out (may be I used that incorrectly, not sure).
Any help would really be appreciated.
Thanks very much.