I'm a long time user of Tree Style Tabs also, but I wish it had a better autohide implementation. The current implementation performs poorly (seems to rerender

I'm a long time user of Tree Style Tabs also, but I wish it had a better autohide implementation. The current implementation performs poorly (seems to rerender the tree structure animations on every unhide), and isn't responsive to touch input for unhiding (although Firefox for Desktop just sucks for touch in general, so there's not a huge loss here). Tabs on side with autohide is the best of both worlds, in my humble opinion. With static tabs on side, the loss of horizontal pixels is mostly inconsequential when running the browser maximized, but really hurts when you want to snap the browser to one side of the screen on a 1080p monitor (and have dev tools on the other side, for instance). I wish some browser vendor would implement something like this natively to make the feature more discoverable. I'm sure it'll be a hit amongst power users and be a powerful differentiator. I remember Chrome having side tabs in development at one point, but it was scrapped for reasons I no longer remember.