As you all know the new Firefox 4 has a sleek look and refreshed layout. Now there is no menu bar (in Windows 7 and Vista) which is moved to a single orange Firefox button.
If you want to access the menu bar every so often, you can enable it manually by clicking the orange button, but there is also a simple tricks to enable or disable menu bar whenever you need it just with a click.
To access the menu bar, just hit the Alt key on the keyboard, to hide it again click the mouse anywhere on the screen.
Hope this simple tip will help you save time.