Comment 2 for bug 587284

This is actually a gnome-panel bug caused by the button being to close to the left edge when compiz is activated. The use of orb style menus on a panel that does not know how to use them becomes obvious. The gnome-panel misreads x coordinates and places the bottom half of the orb just off from where compiz reads the x coordinates for the top piece. Because the difference varies from screen sizes there is no real work around.

However, if you move the button on the panel just a few pixels right the images will sync up.