Love this extension, but the whitelist doesn't work.

Muting background tab works well, but when the foreground tab stops playing media, the last muted tab was not unmuted, even if the option was enabled.

When having audio from two windows rather than tabs, it moves audio focus on the other window, but doesn't move audio focus back on the original window, is it just me? Pausing manually doesn't help either.

I like this add-on because it mutes all tabs that begin to play sounds while another tab is playing sound, and that you can choose to mute a tab manually.
The only reason I didn't give this five stars is because there is no option to "never mute this tab/domain." I like to listen to music on YouTube and browse social media. Whenever I get a message or any other notification from my social media pages, it plays a short notification which mutes my music. There is a place in the Options of this addon where I can choose for sites to be ignored by Smart Tab Mute, but it doesn't seem to work, at least not like I'd like it to.
If I may make a suggestion, it would be lovely to have an option in the context menu to "never mute this tab" or "never mute this site" in the context menu when right-click the tab.

Seems to work very well on everything I throw at it and have had no issues.

Would like to see the ability to blacklist Urls so they are immediately muted.

Smart Tab Mute looks useful, but I am looking for this functionality: I would like to have ONE tab as the "master-audio" tab. (this is a site that has infrequent, but to me very important audio messages). Other tabs may have audio, but should be muted temporarily, as long as the master-tab has sound. When that sound stops, mutet tabs should regain audio. Anyone knows of such functionality?