Great idea, it is a simple but very powerful tool to protect our privacy, and it just works immediately after installing it!
I see it as a perfect demonstrator of the value of the "containers" concept, which makes me think about using the full " Multi-Account Containers" extension.

Worked when I installed it, stopped the next day, maybe due to Nightly installing an update. The container is still there, but it do not open facebook inside it (I am still not logged in outside the container though). I can then manually open the container and open facebook where I am then still logged in

Edit again: the auto focus-switching thing seems to be fixed :)
Edit: Okay I found that Firefox Multi-Account Containers extension and that's pretty much exactly what I was looking for so... :D
Fantastic. I would love a 'generic' implementation of this for any arbitrary site! Though I don't know what specifically goes into containing any single website in terms of maintenance when that website updates or uses unexpected content networks/resources and that sort of thing...
My biggest complaint is that it should not automatically switch focus to the FB page when I open FB in a tab. If not for that, 5 stars.

Great plugin. If you love this plugin, consider getting the Multi-Account Containers extension to use with all the sites you visit: https://addons.mozilla.org/en-US/firefox/addon/multi-account-containers/

Super, konečně se rozhodl někdo postavit facebooku. Jen tak dál ! Moc děkuji :)) super doplněk.

1a Aktion von Firefox, Addon funktioniert klasse