We wanted to give you a heads-up that tab groups in Firefox is going away. You can read about it here. They plan to have the feature removed for Firefox 45, which is coming out in March 2016.
If you are a user of this feature, the TooManyTabs add-on should be a good substitute. You can also browse all Tab management add-ons here.
Hopefully this gives you enough time to try out some of these add-ons before the feature goes away.
Shoot, was working on an add-on build on top of Panorama 
So the plans of making a tab group API have died as well?
For the moment, yes. If your add-on was going to rely on TabView, I’m afraid it’s best to not pursue it unless you want to implement the whole API in your add-on.
I might 
I knew the risk was there though.
Looking at the bugs, Panorama seemed pretty dead.
I think you would have really loved my add-on though 
Thanks for the heads-up btw.
If you create an add-on that at least comes close to do what Panorama does, it would become very popular very quickly.
Just sayin’
If you’re the person to code the panorama replacement, here’s my use cases:
I got a default browser, long running, release channel.
I got a nightly channel, with two windows. One window for landscape and carry around, one window for portrait while I’m at my desk with an external monitor.
Each of those windows have multiple tab groups.
Perpendicular to the portrait vs landscape use-case, they’re mostly task focused. As most of you, I’m working on multiple things in parallel. And some things only once every other day, but reliably more than once a week.
FYI I decided to give it a try myself and port Tab Groups into an add-on. Not sure if it will turn out into anything yet, but so far it’s not looking bad. 
Cool, I’ll keep an eye out.
Let’s hope they don’t remove any API that code relies on though.
Pale Moon also had an extension re-implement Tab Groups:
http://www.palemoon.org/tabgroups.shtml
