Affected versions

• Firefox 77.0b2
• Firefox 78.0a1
• Firefox 76.0
• Firefox 73.0

Affected platforms

• Win 8.1 x64
• Ubuntu 18.04 x64
• macOS 10.15

Steps to reproduce

1. Launch Firefox with a clean profile.
2. Access the https://www.youtube.com/ webpage.
3. Open a 3 or more videos in a new tabs, this tabs have the play button.
4. Select 3 or more tabs pressing CTRL from keyboard + left click on tabs.
5. Right click on first youtube.com tab to access the context menu, then click on "Mute Tabs".
   Hover on first youtube tab and see the tooltip, "Unmute 4 tabs (Ctrl+M)" (see Image1.png) .
6. Restart Firefox.
7. Reload all tabs.
8. Hover on first youtube tab and see the tooltip, "Unmute tab" (see Image2.png).

Expected result

• The previously opened tab remembers it's previous state and is muted.

Actual result

• Between previously opened tabs only the first one is mute.

Regression range
This is not a recent regression, I will come back with regression range ASAP.

Additional notes

• This issue happens if the youtube video tabs have the play button.

In image2.png, it seems only 1 tab is selected.
I think, at step 8, you should select all tabs before mouse hover the mute indicator in a tab.

Because this bug's Severity is normal and has not been changed, and this bug's priority is -- (none,) indicating it has has not been previously triaged, the bug's Severity is being updated to -- (default, untriaged.)

S1 or S2 bugs needs an assignee - could you find someone for this bug?

(In reply to Alice0775 White from comment #1)

In image2.png, it seems only 1 tab is selected.
I think, at step 8, you should select all tabs before mouse hover the mute indicator in a tab.
In Image1.png hover on first tab tooltip indicates that you muted 4 tabs , after restart in Image2.png you will see that only one tab is muted. I expected if previously muted 4 tabs after restart should have all 4 tabs muted.

I have reproduced this issue using builds from 2018. 07. 17 (build ID: 20180717220130) Fx 63.0a1, since multiple tab selection is allowed, every build is affected by this issue. This issue is not a regression as it is reproducible ever since it was implemented.

Marking this as S3 as it appears that S2 (Serious) Major functionality/product severely impaired - is not the correct severity here. Please update if this is incorrectly categorized.

Affected versions

all previous versions listed above up to now Firefox 97.0b5

Redirect a needinfo that is pending on an inactive user to the triage owner.
:dao, since the bug has high priority, could you have a look please?

For more information, please visit auto_nag documentation.