Incompatible with YouTube speed control

[Septolum]

Seems to force 1x playback speed, no matter what speed is set in the player.

[nattofriends]

Seems to work fine in Chrome, but not Firefox.

Edit: This is https://bugzilla.mozilla.org/show_bug.cgi?id=1517199

[Septolum]

Thank you!
I would have spent hours trying to diagnose that myself, fingers crossed Mozilla fix that soon!