http://bugs.winehq.org/show_bug.cgi?id=18446
--- Comment #5 from hasi whynot@nurfuerspam.de 2009-05-13 09:02:03 --- The idea of display drivers being responsible makes sense. I saw some rendering glitches with other applications, as well. However, as they are not as severely affected as PDF Xchange, I did not look into this more closely before.
I am currently using xserver-xorg-video-intel 2:2.6.3-0ubuntu9, my graphics card is Intel 4500MHD. I often see smaller rendering problems, for instance if used in Dual Screen mode (for example, in many cases when a window on top of another window is closed, the refresh of the menu/tool bar in the lower window does not happen until it is resized, etc.). This even happens in KDE applications like Okular.
So very likely, the problem described here IS a display driver issue.