After updating to x11-themes/gtk-engines-qtcurve-0.61.1, my emacs suddenly displays a gray background in the emptry parts of the window, while the parts filled with text are correctly displayed upon white background. I'm using app-editors/emacs-22.3-r1 here. The issue is not present int x11-themes/gtk-engines-qtcurve-0.60.0.
Created attachment 182768 [details] Screenshot
There are several problems with this version, as you can see from the current discussion at http://www.kde-look.org/content/show.php?content=40492 These should be fixed in the next version, which (knowing upstream's trackrecord) will be released very soon.
For the record: fixed in current x11-themes/gtk-engines-qtcurve-0.61.4.