I was loving this extension, having just recently found it... I'd started cleaning up my playlists and suddenly - you guessed it... Youtube made some change that has now rendered it useless. How do I know it was Youtube? Because I even tried downgrading the Firefox browser to what was out in June when I first found it, and that didn't work. Hopefully the creator updates the extension... If so, I'll happily donate some real cash for the effort!