Undo Closed Tab Button allows you to undo closed tabs via a toolbar button or the right-click context menu. FIREFOX 3.6.x, 3.5.x, 3.0.x and 2.0.0.x users can download a compatible version of this extension at http://code.google.com/p/uctb/downloads/list You must add the button by going to View -> Toolbars -> Customize, then drag and drop the button anywhere on any toolbar. Tired of going to Histor