the audio/video content of tabs
When I select a tab I would like to see and hear only that tab. One single mouse click should select a tab, unmute that tab and mute all the other tabs, all at the same time.
Selecting a tab would be equivalent to selecting a channel on a tv.
Then when (with a single click) I select a different tab, it would be equivalent to selecting a different tv channel
Wšykne wótegrona (1)
I like this idea. It is strange that multiple audio streams can play over each other, although I guess that could be useful sometimes. However, I can't think of any built-in feature for that.
If you have a lot of tabs open in a window, you'll notice an extra icon at the right end of the tab bar which drops down a list and has mute buttons. That could be handy for more quickly quieting tabs you don't want to hear, as well as switching to the one you want to hear.
For a complete package, maybe there's an add-on that can do it? Maybe the author of this one could add that as a new feature if you don't find a solution elsewhere:
https://addons.mozilla.org/firefox/addon/sound-control/
There's also a new feature ideas site you can register for and share this suggestion:
https://mozilla.crowdicity.com/
If you do post there, share a link back here.