Hi @BattleHawk The sidebar behavior is currently to remember the last opened "pane" of the sidebar - so if you have opened "Tab Groups" last, it will stay that after quitting and reopening. If you use "Tabs" last, it will stay as that.
If there are any series of steps which cause the browser to not behave this way, please let us know. So far, after trying various combinations, we haven't been able to reproduce the bug that you describe. If you can consistently reproduce it, a screen recording of it would also be really appreciated.
Thanks!
