Window Question

Hi again, I have another question:

I have two sub-applications that can be dragged like windows, and they work pretty well for what I'm working on, except for one problem: when you release a window over another and then try to drag it again, the window above or below it will paste it's background.

How would I be able to fix this?

Check this option for both Sub-Applications:
Sub-Application > Properties > Settings > Window Style > Clip Siblings
(not needed if Window Style > Popup Window checked, thought)