It's because of add-ons like this.
You get a really annoying problem with Firefox, for example it crashes, and when you restart it, every Youtube video then starts playing simultaneously with every other!
What a racket! How fast can you find every tab that has a Youtube video on it and turn the things off?
So then you think: "Well, someone else must've had this problem and come up with a fix". So you search the add-ons and "Yippeeeee! There's a fix for it".
Except, the add-n doesn't work for the latest version of Firefox!!
Why can't Firefox get stable, stay stable and just take a rest for a change? Every week there's a new version and half my extensions have to be updated. OK, slight exaggeration.
Hey, Mozilla! It's not a race to get to version 583, y'know. Nobody cares what number it is, and the bigger it is does NOT mean it's better. In fact, you just annoy people with all these updates.
I was quite happy when it was version 3.6. But instead of 3.7 it jumped to 4. Then 5,6,7,8,9...
will you slow up? Give the poor add-on writers a chance to catch up?
I have a feeling that if you - Mozilla - haven't got the basic core of Firefox sorted out by now, then you never will.
And remember this, Mozilla, Firefox was written for the add-ons. End of. If people don't use add-ons then why are they running Firefox. They may as well use Chrome.
End of rant.
PS. Dear Nikola Kovacs, if you can't find the time to update this add-on, can you please let someone else do it?