Undo a closed Tab(s) or create a duplicate of your current Tab with "Undo|Duplicate Tab" addon.
1. Allows you to restore a closed tab(s).
2. You can easily make a duplicate of the current tab.
3. Toolbar popup UI has two easily accessible buttons (undo & duplicate).
Note: in order to report bugs, please fill the bug report form in the addon's homepage (http://mybrowseraddon.com/undo-duplicate-tab.html).