seems to be working again on youtube as of 6/26. thank you, developers, for your hard work. sorry i was so harsh in my last review, i was upset at youtube

Works great. If you get two rectangles, one grey one red, you need to do a clean reinstall of firefox.

This is an amazing add-on! It's unobtrusive, it's powerful, and it's damned effective, even at blocking ads on Youtube. It is nicely adjustable as well, letting you block irritating elements on a page.

the best add block extension of all time, it has never failed me up on its' task. thank you so much uBlock Origin

Super efficace !