I've been using this since it was new. I'm very frustrated to say the UI/UX hasn't seen any significant update. Containers are still synced separately, so any fresh install of Firefox will have the tutorial UX and the default 4 containers, even after syncing. Also, address bar completion is still monolithic, making it very easy to accidentally open a site in an undesired container. That can be worked around by adding…
I've been using a non add-on store addon for this.. and no idea why something basic like that would not be in the core or this add-on