I think the idea is on the right track (there are a lot of problems with the current 'spotlight' method, such as it being almost worthless for groups that are shown as a stack). But I don't think throwing the result tabs into a group is the right answer. You don't want the user to think that we just messed up their organization, and search results aren't analogous to tab groups. Lets gather the search results and put them front and center in some way that is more abstracted from groups. Maybe just do an awesomebar-type listing?

Punting to the future. This could be a great place for an add-on to step in.

Panorama has been removed from Firefox 45, currently in Beta and scheduled for release on March 7th. As such, I'm closing all existing Panorama bugs. If you are still using Panorama, you will see a deprecation message in Firefox 44, and when 45 is released your tab group data will be migrated to bookmarks, with a folder for each group. There are also a few addons offering similar functionality. See https://support.mozilla.org/en-US/kb/tab-groups-removal for more info. We're removing Panorama because it has extremely low usage (about 0.01% of users), and has a large number of bugs and usability issues. The cost of fixing all those issues is far too high to justify, and so we'll instead be focusing our time and energy on improving other parts of Firefox.