TabBrowser Preferences allows you to add a bunch of additional control to the tab bar in Firefox. For instance, you can close tabs by clicking on them with the middle mouse button. Or you can have it switch tabs just by mousing over them, not needing a left click.

https://addons.mozilla.org/extensions/morei...ication=firefox

I agree with this as a "must have"! This is the 1st extension I install whenever I do a cleaninstall or have formated my drive.