Good extension and useful :) 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 (0), the cache is deleted at the moment, and then you could inmediately set it to the default (10). So we would have either the option to delete or to undo, but I can't create script's addon for Firefox. I hope this idea will be useful to enhance your extension in some way. Thank you.

This review is for a previous version of the add-on (3.7.1.1-signed).