Le quartidi 4 floréal, an CCXXIV, The Wanderer a écrit :
If the list software did this modification for _all_ messages, not just
ones from Gmail addresses, I don't see how it would break threading
It breaks it for the *senders*: they would have the message in their "sent"
archive with the message-id chosen by the MUA and the rest of the thread
connected to the message (in-reply-to and references) with a different
message-id.
Interesting. Do you have any evidence for the idea that it uses more
than just Message-ID? I can't prove that it doesn't, but I've never seen
anything that I recall to indicate that it does.
A long time ago, I experimented with in-reply-to and references in order to
see how gmail decided if a mail belongs in a thread, and my conclusion was
that it relied more on the subject field than anything else. It was a long
time ago.
For myself, one major reason (not the only one) is that the received
copy is often different from the sent copy - modified message headers
(e.g. by adding List-ID), added mailing-list footer, et cetera.
True. A gamil users could check to see if it is possible to obtain that
information. I suspect the misfeature belongs in gmail's web interface,
actually, and the mails are really present in the archive and accessible
through IMAP.