When containers addon was automatically upgraded from 2.4.1 to 3.1.0, all tabs in all containers were removed. When this happened all containers were hidden so to it seems not related to session restore.
Is it possible to prevent this from happening in future upgrades?
I did manual tests in a new ff profile and every time I upgrade from 2.4.1 to 3.1.0 all tabs in all containers were removed.
FF 55.0.2 on Windows 7, in this case.