I have this XP app (win32 C++) that I am just now testing under Windows7 (vista actually, but it does the same thing in windows 7).
I'm surprised that virtually the only issue I'm encountering is the following:
None of the scroll bars in a complex modelless dialog are functioning correctly. The main problem is the scroll thumb is not responding - just stays locked in position if you try and move it. Have had no issues going all the way back to win98, win2000, and winxp. Only in windows 7/Vista just now
But there is no commonality in the scrollbars in this dialog to explain it: One is in a plain richtext control created through a resource file. Another is in a richtext created through CreateWindow. And yet a third scrollbar is in a custom window class. None of them are working correctly (although you can make them scroll by right clicking and selected "Scroll Here".)
So I'm presuming maybe most encountered this a few years ago when porting to Window7/Vista for the first time, but I'm not finding anything in google now.