XP scrollbars going haywire in Windows7/Vista

Question

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.

Answer 1

For modeless dialogs, you have to run IsDialogMessage in the main application GetMessage Loop, so messages for modeless dialogs are not subject to TranslateMessage and DispatchMessage. So I was doing that previously. However, Vista/Win7 doesn't like WM_MOUSEMOVE, and WM_LBUTTONDOWN and WM_LBUTTONUP to be bypassed like that for the dialog (ie they need to stay in the main App message loop). At least this was the problem in my case. I check for those message types now in the main message loop and that solved my problem. Can't explain it necessarily. Also couldn't explain why no one's encountered this previously (could be some idiosyncracy of my set up I guess). THanks for those who looked into this.