oh, that's so sad that firefox developers ruin everything. Media keys doesn't work in the background. Perfect Firefox.
Absolutely useless Quantum

When I try to do anything with media keys it only pauses my player. It does not matter if I change the settings, reinstall the add-on or w/e.

In Spanish keyboard, it only obeys to the dieresis key. Despite having specified a custom shortcut.

Play/Pause Works, but only when Firefox is selected. Forward and Backward don't work at all.

Legendary. Makes streaming at work viable again. Thanks!

The browser has to be in focus for the media keys to register!

Like, wtf is the point of having this add-on, even???
You can't use it when playing a game, or streaming, or, like I said, when you don't have the browser in focus.

Absolutely WORTHLESS add-on, IMO.

For those of you who want to watch/listen to Youtube content while playing a game, use MPC-BE, copy the link location, add the link to the media player and use the media keys to control it. (I can only get pause/play, mute and volume to work, not next/previous.)

The Skipping buttons doesnt work, all it does is pause the videos.

Does what it needs to do, very useful for headphone users with touchscreen.

EDIT
Still an amazing addon, I use it almost every day

I read the description, and I understand that it's not the plugin's fault, but it really does suck how Firefox decided to complicate things like this. Now you can only play/pause, no next/previous track! 5 stars and a donation if this gets fixed. So sick of going back to the music tab.

Installed. Restarted Firefox. It just works. 5/5!

Installed this so I can use the play and pause feature on my Bluetooth headphones works like a charm. Previous / Next doesn't work with YouTube playlists from my experience but I can't imagine that being too far away.

Doesn't work with firefox

Doesn't work on my mac (at least for Google Play Music)