The tabs interface no longer functions correctly, and despite multiple questions appearing on the forum, the threads keep getting deleted. There was one thread that indicated that the tab interface was removed because it made things easier for the programmers. I'm not sure if the post-er was being facetious or not. Obviously, removing features from Firefox would make things easier for the programmers, but no self respecting developer would delete a feature that users clearly want and use, because it made his/her life easier. The idea of good programming is to include features that make life easier for the users. Just like bus drivers cover a normal route, not just from their homes to their favorite bar, the route serves the passengers, not the driver. As I said, no self respecting programmer would just delete a feature on the basis that it was too difficult to maintain. Since there are a few add-ons that restore the proper function of tabs, the location of the tab can't be terribly central to the core function of Firefox, so it is hard to believe that maintaining the feature was all that difficult in the first place. If the "easier" argument is true, why not remove the location bar, bookmarks interface and the main display to make things "easier" and expect freely developed add-ons to take their place, too? All the FF developers would have to maintain is the add-on interface, at least until that was replaced by an add-on itself. Clearly this is just a design aesthetic. I get it, some people want tabs on top, and I'm glad they have that option. There is no reason to be tyrannical about a simple layout configuration. Forcing users to install companion software just to make the core product usable is a poor practice and the reality is the same tyrant who forced the removal of tabs on bottom from the core feature set is going to make changes to prevent the proper function of the add-ons that are required to correct for that poor judgment. The first add-on I found to fix the broken tab interface has almost 300,000 downloads for the current version of Firefox. That is 300,000 disappointed customers trying to find a solution caused by a poor decision on the part of the development team. Don't drive away your users. Drive away the developers who do things that annoy users and claim laziness as a justification.