It seems a glitch deleted my review so I'm reposting to keep users up to date.

Used to be a great extension, almost mandatory. Unfortunately there seems to be a problem that's causing some users to be unable to update to the newer version of the extension (trapping them on version 2.0.121) and this older version is starting to not work anymore. It's probably a good idea to not install until the problem has been fixed.

I'm in currently talking with the dev team via email to find a solution (future update, about:config edit, "unpacked extension") but communication seems to be tricky. I'll update this review when i have confirmation on a fix.

For years this extension worked very good. Lately or a week now, its working in part. I can control the volume with the mouse, but the Video player Control disappeared. I tried uninstalling, re-installing, clear cache, reinstall firefox and then redo everything, still the issue the is same. Basic features disappeared or are not working. I read reviews here, some comments talk about this but not similar issues.

It worked fine for the first time, than disappered for some reason if reload the site.
Totally fine in private mode DKW.
PS. Tried disable others addon or install previous version. No use.

I love it, youtube videos that starts at a low default volume instead of blasting me out of my seat. Awesome !

Quite enjoy this extension. I have noticed the button for rewinding the video to the left of the pause button remains visible for me even when the video bar hides, though it could be due to my many other youtube visual scripts. Also the older update had a much less noticeable opaque box behind the controls that I preferred; an option to adjust the opacity like with the cinema mode would be nice.

Been using this for years, a must-have!

One recent bug - occasionally when using the playback speed wheel while a video is playing, then navigating to another open browser tab, the video will return to 1x speed and won't be able to be altered without refreshing the page.

Good for everything, only issue is that on every device i've used the firefox version on the audio breaks above 8x speed

Edit: All of my issues have been fixed so I am changing the score to 5.

Missing "Videos per row" feature!!
Please add the "Videos per row" option (under Appearance) to the Firefox version! It works great on Chrome and it’s the only thing missing here.

Never had a problem with the extension until now, since the last update when i am in full screen mode the video isn't taking the full screen space (3840*2160) , instead i have a grey border that i can't seem to remove.

Edit: Changing my review to 5 stars because I now think this issue comes from Youtube itself and not the add-on

Beside this issue the add-on is great, as i said never had any problem for years before Youtube decided to mess up the UI.

Thanks for great extension. Thanks for returning to firefox addons portal. For those who are having trouble with the extension, please check if the "User Agent Switcher" extension is installed - they do not work together.

And a few hours after I wrote the review Mozilla allowed for the Jan 30th update (v2.0.131.1) to go through and it actually seems to be working again. Thanks, boss.

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I am seriously lost at this point and have no idea what is happening anymore. Been using this add-on for a few years now without any issues, but something went seriously wrong a few days ago.

Are there any dependencies to other add-ons?(if that is even a thing?)
Once I removed/disabled ViolentMonkey (wasn't running any scripts for the past 6+ months or anything youtube related to begin with) most of the functionality just stopped working or is malfunctioning and re-enabling the add-on brings the functionality back.

Theme function just keeps reverting to "Firefox Alpenglow dark" theme regardless of whether I switch to a different theme or I uncheck the "Dark Theme" option all together.

Any Video Player options just don't work. Full-stop.

Any attempt to revert to an older version(2.0.130.1) or reinstall the latest version(2.0.131) of the add-on does not seem to help.

Going to keep the review at 5 stars because it is most likely an issue that affects me only and I seriously love this add-on.

Probably the best youtube addon tho sadly while the latest update fixed the controls alignment to the player it broke the auto playback speed so i had to roll it back to the clone of 2.0.126.1 version but hopefully that will be fixed soon

Developer, thanks for returning the add-on to Firefox. I always like your add-on. It has a few bugs, but they are small compared to how feature-rich it is