Mozilla Firefox 4 comes with the tab bar placed on top of the navigation bar by default. Moving the default tab position is obviously a significant and to some extent controversial change to the Firefox UI. Some of the users like that Firefox is finally in the same army of the browsers like Opera, Safari and Chrome, while some, especially those long time Firefox users which are used to bottom tabs, don’t like it.
If you are one who don’t like this change, you can easily move tabs back to the bottom. See below :
1. Open Mozilla Firefox 4, right-click on Toolbar and deselect “Tabs on Top” option for the tabs to appear below and bottom of address bar.
2. That’s it. As soon as you uncheck the option, you will have the Tab bar on bottom.