Pop up menu in Xubuntu

[Bill Stanley]

How can I disable the pop-up menu on Xubuntu 12.04.  I am referring to 
the menu that pops up at the bottom of the screen whenever the mouse 
moves to the bottom of the screen.  It is rather distracting and it 
interferes when I am running a Virtual box VM in full screen mode. 
Preferably, it could be activated when a keystroke (Super key) or a 
combination of Keys is pressed.  Other than this, Xubuntu is acceptable.

Bill Stanley