Facebook container goes into infinite loop when "Limit to designated sites" is checked on

[mduchev]

When we have "Multi-Account Containers" extension installed, we have the option for each container to "Limit to designated sites". However, if we set this checkbox to true on the Facebook container, we won't be able to open any of the sites that are in this container. Whenever we try to open any of the sites (e.g., facebook.com), the browser goes into infinite loop of opening and closing a new tab.

• Multi-Account Containers Version: 8.0.1
• Operating System + Version: macOS Monterey 12.0.1
• Firefox Version: 94.0.1 (64-bit)
• Other installed Add-ons + Version + Enabled/Disabled-Status:

  1Password extension (desktop app required) - 4.7.5.90 - enabled Amazon.com - 1.3 - enabled Bing - 1.3 - enabled DuckDuckGo - 1.1 - enabled Facebook Container - 2.3.1 - enabled Google - 1.1 - enabled Privacy Badger - 2021.8.17 - enabled Search by Image - 4.1.0 - enabled To Google Translate - 4.2.0 - enabled uBlock Origin - 1.38.6 - enabled Wikipedia (en) - 1.1 - enabled Checkmarks - 1.6.1 - disabled

Actual behavior

The browser goes into constant loop of creating and removing new tabs and the actual site never opens

Expected behavior

The browser to open one instance of the selected site

Steps to reproduce

1. Install Multi-Account Containers extension and have Facebook containers enabled
2. Click on the "Multi-Account Containers" extension from the toolbar
3. Click on "Manage containers"
4. Click on "Facebook" container
5. Enable the checkbox "Limit to designated sites"
6. Try to open facebook.com or any of the other sites that are in this container

Notes

If we disable the checkbox, then everything opens as expected. In the demo gif below, you can see the infinite loop. At the end of the gif facebook.com opens successfully, because I've disabled the checkox runtime.

Config & demo

[creative-resort]

Tip: use the dedicated Facebook Container add-on. https://addons.mozilla.org/de/firefox/addon/facebook-container/

Facebook needs to access other domains, too — but you are disallowing that by applying this restriction.