Found in

• Nightly 106.0a1

Affected versions

• Nightly 106.0a1
• Firefox 105.0b7

Tested platforms

• macOS 12

Affected platforms

• macOS 12

Unaffected platforms

• Windows
• Linux

Preconditions

• Have "Open previous windows and tabs" checked in about:preferences.

Steps to reproduce

1. Launch Firefox.
2. Open a few tabs/websites.
3. Select all the tabs using the "Command" key and close them via context menu.(Right click on any of the tabs and select "Close x tabs".
4. Re-launch Firefox.
5. Hit "Command"(⌘)+"Shift"(⇧)+"T".

Expected result

• All the closed tabs should be restored.

Actual result

• Nothing happens.

Regression range

• Not a recent regression, Firefox 60 is also affected, will do some digging for a regression as soon as possible.

Additional notes

• On Windows and Linux the shortcut restores the previously closed tabs after re-launching the browser.
• On Chrome, tabs are restored one by one if the browser is re-launched.
• This shortcut works if the user doesn't close the browser. If one leaves 1 tab open and closes 4 others, the other 4 tabs are restored.

Suggesting an S3 severity since the user is able to manually restore the previous session from the hamburger menu.

(In reply to Ardelean Oana from comment #0)

Steps to reproduce

1. Launch Firefox.
2. Open a few tabs/websites.
3. Select all the tabs using the "Command" key and close them via context menu.(Right click on any of the tabs and select "Close x tabs".
4. Re-launch Firefox.

On macOS, closing all the tabs just closes the window, it doesn't quit the browser. So as far as Firefox is concerned you haven't quit, and you're not "relaunching". Even if you then did something else to "really" quit, we register the window as being closed first and then don't restore it. That's why tabs aren't restored in this way. This is a dupe of bug 736974.