Unfortunately this seems to be common behavior that a couple of users have pointed out this week, where firefox only retains the info in the last window closed, instead of the primary one. I'm unsure of how to make it remember the first window, or restore the first window, but I'm looking into it. Maybe someone else will know.

Thanks for the answer. Good to know that I'm not the only one with this problem. One suggestion I have would be to - similar to bookmarks - have an option to save the current tab configurations. In this case, if I accidentally close the Firefox windows in the wrong order I could just reload my saved configuration. That might not get all the "dynamic" tabs back that I also had open, but in my case at least I'm more concerned about quickly restoring all the pinned tabs.

Have the same issue frequently. Would it be too much to ask to have a way to save a current set of tabs at will, with a date and a name if wanted? I would prefer this to having to painstakingly search thru history to find my old deleted pins and tabs.

Did you you look at "History -> Recently Closed Windows" ?

Firefox should remember three closed windows as set via this pref on the about:config page.

• browser.sessionstore.max_windows_undo = 3
• https://support.mozilla.org/en-US/kb/about-config-editor-firefox

Thanks cor-el. I guess it helps to be able to read :) That's exactly what I was looking for, hidden in plain sight.