Firefox by default uses Ctrl+Shift+T (seriously…) to undo tab close. This is rather bad, because there is no way to change the key, not even on a Mac in the Keyboard Preference pane. This addon provides a way to add a customizable shortcut to undo tab close. By default it is binded to Ctrl+Z.
NOTE: For some reason sometimes the shortcut doesn't work if the input focus is on the web page. My guess is it has something to do with the fact that the shortcut key may be already binded by Firefox itself (for example Ctrl+Z for the undo function). In that case a workaround is to click the side bar and press the key.
