Tab Groups was what really set Firefox apart from other browsers, and it was the one feature I was really, really going to miss in FF57. I'm glad a wizard like Fonso managed to create a Webextension that retains much of the functionality of Tab Groups, even if it's not 100% there. Thanks, Fonso!

The only real problem (so far) that's not due to limitations of Webextensions: The toolbar icon is VERY hard to see in "dark" Firefox themes... think dark grey on even darker grey/black. I'd like the icon revised to include some color/fill so it stands out no matter what the Firefox theme colors.