This has been bugging me for ages. Happened on Windows 10 and now on Windows 11. I start watching some video on YouTube or whatever, decide it's not useful/what I want, stop playing it, close the tab or navigate away, but if my device locks, the controls for this old, discarded video, that I didn't want to watch, are on the lock screen. I wouldn't mind if it was a video I was currently watching but it's somehow remembering the last thing I started to watch. I can see no hint anywhere else that it's still active in any way at all. The only way to get rid seems to be to close Firfox. This is very annoying because it seems you can't watch anything without Firefox remembering it and putting on the lock screen until the end of the session, so it could be cluttering things up all day unless I close everything and (in my case, because of prvicy settings) delete cookies and log myself out of most sites. I've tried multiple searches but all I've found here is a post about turning off media.hardwaremediakeys.enabled but I don't actually want to do that, I just want Firefox to forget videos when I've closed the tab or navigated away from them. Elsewhere I found a suggestion to disable dom.media.mediasession.enabled but that setting isn't found. Any help much appreciated.