A few months ago I got a Radeon HD 5770, and whenever I enable compositing, menus will sometimes fail to show up until I hover the mouse over them. For example, I can click on the XFCE applications menu and hover the mouse over an application category (which should make a sub-menu appear). The sub-menu will not show up until I move the mouse over the region where the sub-menu should be. Once I actually move the mouse over the sub-menu, it will show up, almost as if the sub-menu forgets to draw itself until the mouse is over it. This happens in other applications as well. It happens with Compiz, as well as XFWM4 (when its compositing is enabled), however it never happens when compositing is disabled.

Anyone know what I might be able to tweak in the Catalyst or Xorg configuration to make this work correctly?