Taskbar and Panel items are not properly placed and colours are also affected. See attached screenshot. Only appears to affect Xfce items. Reproducible: Always Steps to Reproduce: Always there. Using Ubuntu Dapper (Xubuntu) for testing on IBM Thinkpad 600E. Recent update created problem. GTK 2.8.8
Created attachment 359 Screenshot showing corruption
Ubuntu Dapper is an unstable work in progress distribution. I've never ever seen that elseware. I don't think this is an xfce bug.
I agree with Olivier. There is no way this could be caused by anything Xfce does. This looks like an X driver issue to me and possibly something in gtk/cairo or similar library.