When Fennec is killed, my recently closed tabs are not restored in my "Recent Tabs" panel. Additionally, because I have my browser set to always restore tabs (the default), the items in "Tabs from last time" are really old, and not particularly useful. In this bug, I think we should make sure recently closed tabs are persisted across app runs, but in the future I think we should consider hiding the "Tabs from last time" section for people who have their tabs set to always restore.

I'm afraid I can't reproduce this (in FF44 and today's Nightly): - I've closed some tabs - made sure they appear under Recent Tabs - switched away from Firefox and killed it by swiping it recently the task switcher - relaunched Firefox and all my recently closed tabs where present, as large as life and twice as natural In the session store code, we attach the closed tab data to the window during restore and then later save it back out as needed, so the data shouldn't get lost. The only thing that should be able to go wrong would be a corrupted session store file, which would probably be bug 1190627. As for the tabs from last time, the easiest solution seems deleting out-of-date sessionstore.bak files during startup if we're restoring tabs, which automatically hides the "tabs from last time" section.

Looking a bit closer, one thing that theoretically could go wrong is that the session store might not be quite ready when the "ClosedTabs:StartNotifications" notification arrives. Seems like I should add some logging for that, too.

Review commit: https://reviewboard.mozilla.org/r/49229/diff/#index_header See other reviews: https://reviewboard.mozilla.org/r/49229/

Comment on attachment 8746026 [details] MozReview Request: Bug 1266223 - Add logging for session store closed tab data messaging. r=margaret https://reviewboard.mozilla.org/r/49229/#review46105

Margaret, can you reproduce this with logging enabled?

(In reply to Jan Henning [:JanH] from comment #8) > Margaret, can you reproduce this with logging enabled? I haven't seen this happen recently, and I can't reproduce when trying right now. I don't often look at my recent tabs panel, but I can try to look more closely to see if this happens again.

I've seen this myself now. Unfortunately, I still don't know what exactly went wrong, but my suspicion is that the problem is not in persisting the closed tab data, but in sending it from the session store to the Java UI. After switching to a different tab and back to about:home, which triggered a cycle of ClosedTabs:StopNotifications and ClosedTabs:StartNotifications, the closed tabs were properly transmitted and reappeared in the recent tabs panel.

Haven't really seen this recently.

Removing leave-open keyword from resolved bugs, per :sylvestre.