Comment 7 for bug 635258

I get the same problem with emacs, so it looks like this affects any application using bitmap fonts.
From the look of it, single characters are more affected than large areas (even on normal repaints where nothing has changed, eg switching desktops), so my guess would be that something isn't properly clearing bitmaps at their edges before copying them.
Using Maverick + compiz + gnome. Worked fine in 10.04