Move tabs below the address-bar
In Firefox 29.00 and above versions, the below solutions may not work. Firefox has also changed its core theme. If you want to get the old theme back and also want tabs to show below the Address-Bar then the solution is to use Classic Theme Restorer add-on.
Another way to solve this issue is to use Add-On-Bottom add-on. It requires no browser restart and there are no complicated options to set. Install this plugin and enjoy using Firefox the way you want it.
The theme restorer plugin brings back the old Firefox design and features, where the second add-on does just one job; it puts tabs below address-bar.
Firefox has made lot of changes in the past few updates, one of which was moving the Tabs to the top. How can I move them back below the address bar, like they were in the past?
Open Firefox: right click on blank space in front of the last Tab. Here, uncheck the following option:
Tabs On Top
That’s it: tabs will now show below the address bar.
Open Firefox and type the following [without quotes] in the address bar:
If a warning message shows up, click on:
“I'll be careful, I promise”
In top-left corner, a Search Bar will show up. Type the following in it;
An entry will show up. Change its value to False.