Firefox only: You have a bunch of tabs open and decide to click like a fiend to free up memory, and bam! You close a tab you wanted open. Save it without diving into the history. If you're well versed in your Firefox keyboard-fu, you know that pressing Ctrl+Shift+T will bring the last tab you closed back to life. If you close multiple tabs however you've got to re-open several tabs to get to the one you wanted. Undo Closed Tab Button is a simple Firefox extension that adds three menus to your user interface. A button is placed on your toolbar, a tiny button is placed on the tab bar, and an entry is inserted into the right-click context menu. The menu placement ensures you'll never be more than a quick click away from resurrecting the tab you just accidentally closed even if you close a bundle and realise there was one in the mix you wanted to keep open. Undo Closed Tabs Button works wherever Firefox does. The previously mentioned Tab Mix Plus extension adds this functionality on top of a whole lot more, but if you don't need to bloat of Tab Mix Plus, this simple extension is a good alternative.