I've also been able to hit this with openbox and xcompmgr or cairo-compmgr, and only with gnome-panel. It may not be a gnome-panel bug, but a common behavior in compositing managers that can be triggered by gnome-panel.
I've also been able to hit this with openbox and xcompmgr or cairo-compmgr, and only with gnome-panel. It may not be a gnome-panel bug, but a common behavior in compositing managers that can be triggered by gnome-panel.