META: Replies and threading

[Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx>]

On Mon, Jan 15, 2024 at 6:37 AM Ray Andrews <rayandrews@xxxxxxxxxxx> wrote:
>
> So if I want a new subject, it's not sufficient to change the Subject?  I mean it must be a fresh post, not a reply?  But I hardly ever do that anyway, and not recently.  If it just happened it wasn't me.  Please advise.

I think this comes down to different user agents doing different
things with threading.

I sent a message on the thread with subject
  Slurping a file (was: more spllitting travails)
When Ray replied to that message, his reply ended up back on the
thread with subject
  Re: Slurping a file
(that is, the thread Ray created for the unrelated "quick and dirty question").

Ray's header says
User-Agent: Mozilla Thunderbird

I suspect Tbird has gotten its References: headers crossed and is
keeping everything Ray says on the thread he created, whether there's
been a change of subject or not, and using the subject of the message
that Tbird originated rather than the subject of the directly
replied-to message. Maybe another Tbird user can experiment or
comment.

Gmail threads almost entirely by subject without using the
in-reply-to/references message-ids. It ignores both Re: and Fwd:
prefixes when doing that, too, so more confusion got introduced when I
forwarded Mark R's message and replies started referring to that.
Some other UAs use only in-reply-to/references (see
https://www.zsh.org/mla/users/2024/threads.html for what this looks
like) while still others try to intelligently use both.  In any case,
the (seeming) Tbird behavior mentioned above makes Ray's messages and
replies to Ray's messages seem to leap back and forth among different
threads when viewed in other UAs.

In short this is not looking like something Ray did intentionally (at
least, not after that first "quick and dirty") and it's partly my
fault for updating my Subject without breaking the references chain,
although I did it that way on purpose without expecting it to induce
this side-effect.

So to Ray's question above, yes, it's best if a completely new topic
has both a new subject and is a fresh post.   With respect to emending
the subject in a reply chain when the topics are connected, I'll
probably continue to do that unless it seems to be causing more harm
than good.

Sort-of on the topic, Tbird using HTML format with <blockquote
style="white-space: pre-wrap">
for responded message excerpts makes it nearly impossible to
distinguish nested replies and seems to encourage things like random
font size/color changes and "MUA" getting chopped down to "M" when Ray
edits his responses.  Any other Tbird users have helpful tips?