Extra menu bar when app menu is disabled
![ugly-menu](data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==)
With the app menu disabled you get both the icon in the top-left corner, and a new menu bar for a "Rhythmbox" menu. Both have the same content, although drawn differently (shell chrome vs gtk menu). Presumably the gtk menu should be suppressed.