What's the correct way to close/restore tabs? (currently tabs are restored incorrectly)

[crowbardispensingcore]

New to Firefox as well as Sidebery. When I close the browser, reopen it, and choose Restore Previous Session in History, all my tab groups are flattened, and panels are lost as all tabs are now in default panel. I made sure I'm using Session Storage, even toggled it several times, but it still behaves the same. I also granted Sidebery all the permissions. What should I do? Appreciate any help!