https://bugs.winehq.org/show_bug.cgi?id=42038
--- Comment #7 from Nikolay Sivov bunglehead@gmail.com --- Created attachment 66202 --> https://bugs.winehq.org/attachment.cgi?id=66202 patch
I made some progress on this. Apparently it very much depends on window visibility state, and that's why tests didn't give results.
One remaining issue with attached patch is potentially unrelated to scrollbar handling. The problem is that IsWindowVisible() test fails when compare views are displayed initially. That happens because Afx:xxxx window up parent chain does not have WS_VISIBLE style. While it does on Windows. Full chain ScrollBar -> AfxMDIFrame -> AfxFrameOrView -> AfxMDIFrame -> Afx:xxxxx:xxxx... All windows up to the top one on this list are "WS_VISIBLE"-visible. Anyway, with this patch it's enough to type on char to make scrollbars responsive. Please test and report if you see other problems with it.