MSDN:
Zitat:
If you're hoping to make a temporary popup control in your window and want to use CS_DROPSHADOW to reinforce the fleeting nature of the popup, you can't use it with WS_CHILD -- it just ignores CS_DROPSHADOW. You'll need to make your control be WS_POPUP and then position it where you want it when it opens.
MSDN:
Zitat:
Windows created from a class with this style must be top-level windows; they may not be child windows.