Adding an already opened page to open in a specific container in future should be an option. As of now it only shows option to add to default continer.

Very useful for privacy and multiple accounts on the same service. I only wish the containers and settings would sync through Firefox to other browsers. It's a big pain to add them by hand to multiple computers.

The concept is great and execution has come a long way to make it a generic version of "Facebook Container" addon. A nice way to set and manage user preferences is needed, though.

I really like this extension. It's potentially a much better solution to the "I want to keep my work and personal lives separate" problem than other browsers (see profiles in Chrome). I hope the interface for setting default tabs for domains becomes a bit more robust, and that the interface improves for opening existing tabs in specific containers. I know these are under discussion so I'm optimistic. :)

Absolutely great add-on!
Should be a built-in (or added by default) feature.
It's my No#1 tool for keeping services separated from each other, e.g. Facebook separately contained, News websites with their tracking cookies separately contained, other user accounts/profiles in various other websites and/or services w/o any association between them all.
It's like having multiple, persistent "Private Browsing / Anonymous" tabs with the ability to define a persistent default container for every website (e.g. clicking a Facebook link will always open up in a pre-defined Facebook container tab).
I love it and use it all the time!

Very good idea, needs more work, but nevertheless extremely useful in 2019s internet

Please, please, PLEASE allow us to backup and restore settings with Firefox Sync. Batch categorization of sites in the bookmarks manager without the subsequent "Open this site in your assigned container?" notification would be great as well. This will be the best extension ever if you can get these two things done!