Greate work! This is exactly what i need. Perfect!

It is perfect, fix the FF issue when you accidentally close the pinned tab windows first. Thank you, you saved tens of hours to restore pinned tabs. The pinned tab sets it is also very useful!

fast, easy, should be a basic thing, thanks so much for this!

Works as expected. I do not understand why this isn't standard in any browser. Thank you!

A recommendation:

https://github.com/Drive4ik/simple-tab-groups/issues/286#issuecomment-787110861