For anyone trying this, make sure not to have any google related tabs open because this add-on mess everything up.

In my case I had multiple tabs with Youtube and Google searches and some Youtube tabs turned to Google searches with the contents of the closest tab with a Google search, other tabs with Google searches got "infected" with their neighbors content basically having me end up with replicated tabs, and because the "Go back" button was greyed out I couldn't recover my previous content.

Then I couldn't even delete the container 'till I restarted Firefox without the "Restore Session" enabled.

All in all just awful.

I'm not saying it doesn't work however. Should one not use Firefox with saved sessions it might do just fine, I just won't be using it myself.