How to allow all and just block some sites. Rated 5 out of 5 stars

Hello, first I would like to thank you for your addon, works perfectly.
It it there a way to allow all sites and just block some sites with a simple right click, or creating a black list site?
That option would be really nice for daily use in some personal computers where we just need to block some flash of webs that we usually visit each days.

Thanks :)

This review is for a previous version of the add-on (