https://bugs.winehq.org/show_bug.cgi?id=20695
--- Comment #23 from Luke lukebenes@hotmail.com --- Nikolay, Now that Wine 1.9 is here, could we please test your fix? WinMerge is fully Open Source.[1] Would the scrollbar code provide any hints as to what's going on here?
[1] http://winmerge.org/downloads/source-code.php