why does FF take up the entire desktop?

[Joshua Zeidner]

Hi,

  Whenever I maximize Firefox in Ubuntu, it takes up my whole desktop.
 Its really irritating because I have to press Alt-F9 to minimize it,
as the window controls are gone (it super maximizes it, the header on
the window is not visible nor is the other Gnome desktop controls).
Any ideas on why this is happening?  This is the Gnome environment.

thanks, jmz