This is without a doubt the best Firefox extension out there.
This shouldn't be just an extension, it should be a core feature of Firefox.
Having this integrated into Firefox by default will bring probably the best differentiator Firefox can have on the market.

The only request I have is to make the container list hierarchical (closer to what bookmarks look like). Because at this point I have one container per site and it's hard to manage them.

And this could have so much potential to grow. Either do a client side suggestion engine where it creates containers for the sites you usually visit and suggest connections for sites that are part of the same user group but are on different domains (like maybe you want to connect Gmail with YouTube and with drive under one container).

Please don't ever give up on this feature. I hope you integrate it into core Firefox, but if not, at least work on improving this standalone addon. I think it's the last thing keeping me on Firefox. If this goes away, I don't know what browser will help me navigate the stormy oceans of the Internet.

Thanks for all your work!

every time I open a new link? This is so annoying!
"Open this site in your assigned container?"

This addon is the only reason why I quite brave browser and started using Firefox again.

It breaks sites when placed in a container and I am unable to remove them from a placed container. Consequently leaving the site inside a container without being able to revert it back to a normal tab. Even trying to open it as a normal tab does not work since it only reopens it in the same placed container tab.

Powerful, indispensable, thank you. I consider this functionality as core as all the other default sync items.

How do I remove "Open this site in your assigned container?" every time I open a new link? This is so annoying!

I like it and I find it useful. A better interface should be provided in order to make it easier to manage websites. If the URL is too long the deletion icon is not visible/selectable. Also it's not possible to manually add a domain or use wildcards.

It's very useful extension, It's solves the use cases works well

Good extension, but need redesign and responsible design, and zoom settings too

This add-on is not working as advertised. When closing multiple windows (or sometimes even just one) all the assigned containers are lost on restart. Also, closing and undoing the closing of some tabs causes the container to be lost as well.

Absolutely love this extension. It's brought a long time chrome user over to firefox.

No longer is there any need to have multiple windows open for different webmail logins.

I can stop sites from tracking me by doing web searches in different containers.

Brilliant!

I administer multiple web apps, across multiple environments. Very useful when you need to test as a user (in one or more environments), while viewing/modifying as an administrator simultaneously.