Internet Explorer 9 placed the address bar and tabs in the same toolbar resulting in a compact user interface. Firefox 4 removed the title bar (on Windows), thus saving precious vertical space. The best of both worlds is to combine the address bar and tabs in the top toolbar of Firefox 4. The resulting user interface is super-compact and looks like this:
This can be achieved easily:
Right-click in any empty space beside the tabs and choose Customize. Move the address bar and any other buttons you need to beside the tabs in the top toolbar. For example, I find that I only need the Forward and Back buttons in addition to the address bar.
You no longer need the Navigation Toolbar, which held the address bar. Right-click again and disable the Navigation Toolbar.
The orange Firefox button still remains in the top toolbar occupying a lot of horizontal space. Install the App Button Remove addon which removes it.
You are almost done! It would be nice to limit the size of the address bar. A good way to do this is to provide its minimum and maximum length. One way to do this is by using a Stylish script. Such a script can be found here, modify its length to suit your purpose.
Congrats, you now have a super-compact Firefox that maximizes your screen space! 😊
Tried with: Firefox 4.0