http://bugs.winehq.org/show_bug.cgi?id=10933
--- Comment #15 from Clinton Stimpson cjstimpson@utwire.net 2008-06-29 21:43:40 --- The xrender-patch is not entirely correct (or maybe not correct at all).
I haven't had much time to look at this, but I got as far as a possible hint towards gdi being part of the problem and that possibly xrender and gdi are out of sync with respect to the current font.
It looks worse when the main window is larger. So the screenshot you saw might be from a higher resolution monitor.