How to undo close-tab with 1 click in firefox

There have been many a times wherein we close a tab by mistake using Firefox, and if we wish to undo-close it, we either use 'Tab Mix Plus' or 'Ctrl + Shift + T' key combo to undo close the tab. There is a much easier way that Firefox lets us do.

Simple, just middle click on an empty area where the tabs reside and voila, the closed tab comes back.

Again, just middle click on an empty area in the Tab Bar. Thats it !