Panorama forgets where I've filed tabs in tab groups

Question

I've been noticing this since last fall in Firefox 4 nightlies.
Let's say I have around 60 tabs. I open Panarama, create some tab groups, then drag my tabs to the group where I want it to live.
Over the course of several Firefox restarts, my filing gets lost so that tabs go back to where they once were.
My profile was made last fall specifically for Firefox 4 -- I shouldn't have to create yet another one. I've deleted all my tab groups, then started from scratch to no avail. I've also tried disabling some add-ons like xmarks and session manager, which I imagine might impact Panorama.
Another approach would be to delete (in the file system) everything Firefox knows about Panorama so that record-keeping starts from scratch. How do I do that?

Answer 1

With the help of information from user, ptressel, in [https://support.mozilla.org/en-US/questions/1032154#answer-673322 a post here about the existence of sessionstore.js when version 33 was released], I was able to easily recover my tabs and tab groups as follows:
# close Firefox and, perhaps, allow a few seconds (30s?) for any final closing of files;
# check to see if you have a sessionstore.js file in your profile folder, named like the one I documented in my original post above;
# if it is not timestamped prior to the discovery of your problem, open the sessionstore-backups folder;
# check if the recovery.js file is suitably timestamped and, if not, the recovery.bak.
# At this point, you are likely to find that none of them are prior to your problem occuring. If so, open your backups of this folder and go through steps 2-4 to find a file prior to your problem occuring.
# When you find a file, copy it to the root of your current profile folder and name it, "sessionstore.js"
# Open Firefox. Mine opened up as desired.
This is a Windows solution. Sorry I can't comment on other platforms, but I'd bet that as this is just a file copy and renaming, it is likely the same.
For Windows users, you may find you need to sign out and login as an administrator in order to access the backups. You need not logoff your standard account, but do have Firefox closed as described above.
Hope that helps.