It is 2020, still cannot sort the list created.

I get the message -
This add-on cannot be installed as it appears to be corrupt, after the add-on is downloaded.
Please fix it ASAP

Mozilla had a hand in this disaster. iThey should remove it and look up the word 'robust'.--which it is definitely not. it's an embarassment to the brand.
the worst was when i deleted it and artifacts remained in the contextaul menu. it took hours to get them out. and i'm still not sure if i did. Caveat emptor!

update 5-4-20 I get it now they won't allow install from tor browser cuz they want to track all your logins using the so called private containers. BS Also Mozilla login here is a royal PITA maybe they don't want more reviews/
WHY IS IT RECOMMENDED? WILL NOT INSTALL: ERROR: FILE IS CORRUPTED

Just like Moz://FifthAxiom : this module is great "on paper" but it lacks a lot of options and default behaviours to be useful in an everyday situation.

You should be able to easily manage the list of sites (or wildcards) assigned to a container, this basic setting should avoid new tabs (if the domain name does not match) to be opened in the same container thus breaking the tracking.

Please improve this great promising tools.

"Keep parts of your life separated".

History isn't separated.

It seems great on the paper, but lot of websites are unable to load. This includes Faebook, Messenger Linkedin, Outlook mails, etc..

When you assing site to container and tell it to always open in that container, site won't load on private browsing. It was working fine a couple of days again. Please fix it. Can't use Google when in private window.

Sadly, this feature that is already in the default Firefox for Windows features isn't integrated to Android's version...

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THIS WONT WORK (THE EASY WAY):
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Misleading quote: "Avoid leaving social-network footprints all over the web (for example, you could use a Container tab for signing in to a social network, and use a different tab for visiting online news sites, keeping your social identity separate from tracking scripts on news sites)."

You'll need to add an option to change its behavior. When opening a site in a container (e.g. Bing-search) - clicking a link - the new (unassigned) site will stay in the same container thus enabling tracking. Pretty useless this way. Although useful for using different profiles, it's not secure/private.

Options to add (user-decided behavior):
- Open new unassigned sites in the default container, a temporary container or current container (you can reassign later)
- Switch/assign (via toolbar button) the current site to different container (assign/move/copy to a new container for site)
- Changing to a new container will open a new tab or use the current tab (a new tab to avoid losing *cursing* history)
- Option to open web sites in their own containers without the user assigning a container (auto-created for TLD's) *
- Possibility to select a default container for a site assigned to multiple containers or use last container used
- Possibility to sort container labels
- Add an overview of which site/data is contained in which container
- Try to also use the omni-box for extra functions (assigned container switching) since the container-label is already there

* When reassigned by user the auto-created container is renamed or merged with an existing container

EDIT 1: Rating lowered from 2 to 1 star until problems are solved. Totally wrong implementation (the omni-box becoming useless and is imprisoned by this add-on). I get the idea but it's wrong. Visiting Facebook, then entering a different URL, will keep you in the Facebook container. Track-track-track. Just too much concentration and handling is needed to keep things real secure. For now this extension is just a kind of identity switcher within the same Firefox user-profile. Why not then just create an add-on to switch to another user-profile with a toolbar drop down-menu? At least that's clear and transparent. This surely isn't! For this to work properly you've to create a container for every URL/cluster of sites you visit. We need Firefox Web Clusters/Containers.

EDIT 2: Found out that sites are currently not even linked to containers (only cache/cookie data) which was not my assumption. It starts your selected container and stores data in that container separating data from other containers. The problem here is that selecting a default container for a specific site results in not being able to switch accounts for that specific site. A contradicting (dis)function.

Abstract/Résumé:
- You can switch profiles by selecting containers in the toolbar-button (entering the URL again)
- Ones assigned to a specific default container, you can't switch profiles
- You'll need to be careful entering websites you're not willing to have in the container since this enables tracking *
- To protect you from tracking you'll need (an) extension(s) that isolates Facebook, etc. from all other containers **

* You'll notice you're logged off from web sites (don't log in but start a new container). This extension is (not) for dummies.
** There's a Facebook container that doesn't work i.c.w. other forks (Google, Twitter, etc.). Also you can't switch profiles.

EDIT 3: For a workable solution install these extra add-ons

- Switch Container (https://addons.mozilla.org/en-US/firefox/addon/switch-container/)

- Temporary Containers (https://addons.mozilla.org/en-US/firefox/addon/temporary-containers/)

Moz://FifthAxiom

Using FF 72.0 & Multi-Account Containers 6.1.1 it lasted for about 15 mins then broke. I cleared all my history including the cache and after that container assignment in the URL tab disappeared forever. It previously appeared using a mouse right click on the tab. Tried bouncing everything and reinstalling it...still dead. I can manage the containers but putting a tab in one is gone. Finally got it working by completely reseting FF and reinstalling it along with my other add-ons.

no possibility to sync with other instances of firefox. Its useless this way. The whole syncing makes for me only sense because I can use the browser at home and at work, but i dont want to mix the contents. Because Firefox does not support multiple profiles, or does not have a user friendly support for profiles, the multi-account-containers would be a good workaround, but if you cannot sync containers, this addon its useless.

Different accounts use the same URL for the same website. There's no way to use this for multiple accounts unless the different accounts had different URL's. Or there need to be better instructions.

Annoying

How many goddamn times do I have to "Get Started"????

This need a better way to add sites to containers.

Does not work with Waterfox