As of today, 28 Mar 2021, Facebook Container 2.1.2 is BROKEN for 78.9.0 ESR 64 bit. It worked in 78.8 ESR 32 bit, but locked me out after the upgrade. When I turn the extension off, Facebook reappears. Remove, restart, and reinstall doesn't help.
[edit] This version WORKS PROPERLY on 78.8.0 ESR 64 bit. I checked it on other versions running on my network, sync'd to the updated 78.9.0 ESR 64 bit.

I like this extension but every time it pulls into a container it wipes history of the tab which is kinda annoying. I can't seem to see a setting for that so that might be a future feature

Instagram tab gets unpinned every time I restart firefox. Facebook and messenger sites are working normal.

It was a 5 star but after the latest firefox update (85.0.2 64-bit) it is slowing down firefox

Overall, the add-on seems to work. I don't like that it displays the little icon over media content. Sometimes making the text a bit decipherable, it is just irritating to know that there has to be a way to place the icon over the social media icon. Maybe I am wrong.

bonne intention. J'attends de voir à l'usage

Can you please allow us to use Instagram DM as an OPTION?