New with Firefox 4 Beta 7 was out with the Status Bar and in with the ‘Add-on Bar’. So, what’s the difference? Other than the name, nothing really. Oh yea, the status bar add-ons bar now has a ‘close button’ so you can easily hide it. To re-activate either right-click on the navigation or tab bar and select Customize… then choose Add-on Bar. Else activate the menu bar via the Alt key and select View >> Toolbars then select Add-on Bar.
ETA: Several more things, there is no longer a progress bar. There is no ‘status’ reports (loading, waiting, Done, etc.). Also now when you mouse over a link the address now appears in the address bar. Looks like there is suppose to be an add-on to replace the ‘old’ status bar. More on this is another post.