Close a range of tabs! by SkyLord

Say, you have a lot of tabs open and hate that firefox only lets you close tabs one by one by clicking that tiny x.
Worse, each tab needs to first be loaded before you can close it.
Even worse, if you click on that x spot too fast, the firefox window minimizes, causing even more pain.
I hated the same aspects of firefox and finding that the only existing addon targeted towards that problem did not work as intended, I just created my own addon.

How it works is simple:
1. go to a Tab a and when there, click the addon icon.
A number should appear on the icon which is essentially the index of the current Tab.
2. go to a Tab b. click the icon again.
3. Now by itself all Tabs between Tab a and Tab b should close.
(excluding Tab a and b themselves!)

From Tests so far I can say that this works almost instantly.
But for safety's sake, please follow 2 just-in-case-warnings:
a) After clicking the icon for the second time in step 2, please wait a short while to be sure that the addon has finished its job.
b) And despite there being countermeasures in the code, it is advised to have tab a in step 1 be the left "border tab" and tab b in step 2 be the right "border tab".
Code wise the other way around should work too but it is not advised.