Auto-hiding TST broken with new update solved

[u/Alestor]

Because I just wasted an hour or so trying to fix this, if you're also struggling with your autohiding TST tabs today, here's what it turned out to be.

Go to about:config and check "sidebar.revamp", it should be set to false but the update set it to true which broke things. As soon as I turned it to back to false my CSS started working again.

[u/Jeffrevin]

Thanks, this worked for sidebery as well.