Hi  !

You undoubtedly will have checked this, but just to be sure :

Is your latest Flash version 27.0.0.187  ?

Would you please check this as well :

Type in the address bar about:config (press Enter) (promise to be careful, if asked)

Type in the search bar and look for the preference :

browser.tabs.showAudioPlayingIcon

Its value should be set to true

You've already tried everything else, so this is all I can think of ......

Thanks for the suggestions. But Flash was already 27.0.0.187 (I should have mentioned that), and that option was already set to "true".

I should add: I now realized that right click on "mute tab" does actually bring up the (muted) speaker symbol, but still without actually muting.

StefanBusch said

Thanks for the suggestions. But Flash was already 27.0.0.187 (I should have mentioned that), and that option was already set to "true".

Bummer  !

I should add: I now realized that right click on "mute tab" does actually bring up the (muted) speaker symbol, but still without actually muting.

Truth be told : you did mention it in your first post ...... I was kinda hoping that the preference set to 'true' might make a difference .

As you have already tried so much, the only thing I can think of now is to give this extension a try :

https://addons.mozilla.org/en-US/firefox/addon/mute-tab-webextension/

Thanks, but this also doesn't help. It works only on the tabs with non-Flash sites.

Mute tab only works with the HTML5 media player and not with the Flash plugin. You would have to use an extension to mute the sound if a Flash player is used. You can search the Add-ons website for a suitable extension.

• https://addons.mozilla.org/en-US/firefox/search/?q=mute

Thanks for clearing that up. I don't see an extension solving this. I would like to suggest to the developers to add an option to mute flash. In Chrome, this isn't a problem.

What bothers me :

You have the speaker icon and it should mute the sound, no matter what content, Flash or HTML5. I can't find anything to solve this mystery, that you haven't already tried, but should I stumble upon it, I will definately let you know.

IMO Flash should be muted, at least since version 49.

https://bugzilla.mozilla.org/show_bug.cgi?id=1276119

StefanBusch said

Thanks, but this also doesn't help. It works only on the tabs with non-Flash sites.

This Mute Tab add-on says it only works with HTML5 media :

https://addons.mozilla.org/en-US/firefox/addon/mute-tab/

But the link to the Mute Tab Webextension I gave you says  :

This mutes every tab regardless of whether it actually contains multimedia or not.

https://addons.mozilla.org/en-US/firefox/addon/mute-tab-webextension/

Hence I suggested it - I am baffled that it doesn't work.

Unfortunately I can't find any solution to this problem, other than to suggest to use (as a workaround) the keyboard shortcut Ctrl + M ......

Does that work  ?

Same issue here, although not only are some Flash clips able to play sound through a tab mute (some are blocked), but some HTML5 content is able to play. I only noticed the HTML5 playing today when I was playing a game where the music played, but the sound effects weren't. I couldn't figure it out until I realized the tab was muted. Unmuting let the sound effects play.

I've also tried about 6 different "mute" extensions and none work. How hard is it to just block all sound on a tab? It seems a simple thing.