(In reply to Dave Miller [:justdave] from comment #0)

When the application is quit or crashes, compose windows which were open at
the time the app quit do not get restored when the app restarts. This means
to continue where you left off, you have to go search out these messages in
your drafts folders in order to resume them (if you even remember you had a
compose window open when you crashed or quit).

It's worse than that. Not only do you have to dig for all those draft compositions in your draft folder (between dozens of stale drafts often left behind by Thunderbird), but I'd bet this also involves dataloss for anything which hasn't been saved by auto-save yet. 5 minutes auto-save interval can still be a lot of content to go missing.

This would be great to have (ux-papercut) also for enterprise environments - e.g. when shutting down at end of day, complete session restore including compositions (per this bug) would avoid that hassle of having to decide on saving every draft individually - of course I want to save them! I'd guess most users don't regularly start compositions to abandon them...

Thanks much Wayne for rounding up the duplicates!

I would contest that bug 1448942 is a true duplicate as it doesn't specifically mention that the compose window needed to be open during shutting down Thunderbird. The user can choose to close composer and save as draft, with intent to continue the conversation a week later - I have added more detail there.

I considered re-opening bug 1448942 but maybe we can edit the title of this one to make it less composer / session specific - I vote to remove the term "Previously open compose window" and replace with "previously edited draft" to bring it closer to the desired business logic. There shouldn't be an expiry on a draft either, so whether I started to reply yesterday or 3 months ago, Thunderbird should pick up the original draft if possible.

I also foresee some technical complications as I have seen older duplicates of drafts after sending, so we also need to make sure that duplicate / older drafts to the same thread are deleted / moved to trash after sending the email.

Thunderbird just told me that I have to restart in order to apply the latest update and that all open composer windows would reopen after restart - they did not dot reopen. Thunderbird only opened with its main window. Due to the message shown for the update notification it is obvious, that reopening should be the expected behaviour - which would also mean that this bug is expected to be solved, while the it is not.