Limit to designated sites" set to true opens any of the Facebook container sites in 2 tabs

[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 one of our containers (e.g., Personal), and we open one site that is in this container (e.g., google.com) and then try to open one site from the Facebook container (e.g., facebook.com), the site from the Facebook container opens in 2 Facebook container tabs.

• 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 opens 2 new tabs of facebook.com

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. Add any site to any of the containers. E.g., I'll add google.com to Personal container
3. Click on the "Multi-Account Containers" extension from the toolbar
4. Click on "Manage containers"
5. Click on the container that we've just added our site to. In this example it's "Persona" container
6. Enable the checkbox "Limit to designated sites"
7. Open the site that we've added in a new tab. In this example, if we open google.com, it should open in a new Personal tab
8. In the same tab, try to open any of the sites from the Facebook container. This can be achieved either writing the url directly in the toolbar, or clicking on a bookmark

Notes

If we disable the checkbox, then everything opens as expected.

Config & demo

[creative-resort]

Facebook accesses also other domains than just facebook.com Find out and include these domains in the container, so they are allowed within it. Otherwise the container will be limited to just facebook.com and Facebook will effectively hop outside of this container for the other domains.

Tip: There is also this dedicated Facebook Container add-on. https://addons.mozilla.org/de/firefox/addon/facebook-container/