For all of you who may use Firebug on a PC, I thought I would pass along a short cut I stumbled upon this week.
The F12 key on the PC keyboard will open and close Firebug within the same browser window.
If you work with Firebug open in a separate window, then hitting F12 from the main window will shift focus to the Firebug window. To get back to the main browser window, you will need to use the mouse, or the Alt-Tab keyboard combination.