Panorama has a very small user base and there's basically no chance that we will enable it by default or even improve its visibility and discoverability anytime soon. In its current form it is indeed quite fragile and causes intermittent test failures here and there when touching platform code. We're not going to spending any time on improving Panorama and its feature or its design and UX - thus it should just be removed from Firefox. Tim Taubert
Unfortunately Mozilla didn’t learn anything from this failed experiment and insists on wasting its limited resources on features that can be best served as add-ons – case in point: the built-in Facebook Messenger!
via Sören Hentzschel