Hide Top Bar
Hides the top bar, except in overview. However, there is an option to show the panel whenever the mouse pointer approaches the edge of the screen. And if "intellihide" is enabled, the panel only hides when a window takes the space.
Insensitive Message Tray
Renders the bottom message tray insensitive so that it doesn't show up automatically when the mouse pointer is placed at the bottom edge of the screen. However you can still access the message tray using Super+M.
