Comment 4 for bug 145658

Sorry about the delay. In Gutsy, this problem seems to be caused by a bug in fglrx, and only when compositing is enabled. There are a host of other rendering glitches that also occur when compositing is enabled. xfce compositing works "most of the time", but some windows often show garbage video memory. In Hardy none of these problems occur anymore, so I would mark this as 'fixed' rather than 'invalid'.

In case you're curious, I've also attached my xorg log.