Good and useful extension :) Rated 5 out of 5 stars

It works nice. This extension has given me an idea to clear also the cache of the recently closed tabs, taking advantage of the fact that if you set the about:config browser.sessionstore.max_tabs_undo to zero, the cache is deleted at the moment, and then you could inmediately set it to the default (10) or the number you have choosen before. However, if the values set in browser.sessionstore.max_tabs_undo were five, four, three, two or one, all closed tabs are deleted but the last five, four, three, two or the last one. So we would have either the option to clear all cache, to clear all but the last X closed tabs, or to undo all or the last. I hope this idea will be useful to enhance your extension in some way. Thanks.

This review is for a previous version of the add-on (3.7.1).  This user has a previous review of this add-on.