From: Jeff Caton on
How can I determine if a layered (=click-through) + HWND_TOPMOST window
is the current top level window?
It's not possible to determine this by using GetForegroundWindow()
because layered windows are being ignored.

I can't believe that it's completely unknownin which order the windows
have to be painted, so I guess that Windows does have this window
somewhere in a collection, right? I was hoping that by going through
this collection, I could find out what's the real foreground window.