I was referring to the larger issue of making subject lines
compatible with all readers and under all configurations.

Of course that's impossible. Someone will program a bigger bug. But if
there is a known and common issue (the bug), and an easy fix, (avoid
colonized prepends), it's probably worth spreading and doing. Alas,
working around software will always be an issue.

I was referring to your reply to my post where I added an extra "OT:
(was..." and your reader posted only " OT - OT:" If your app didn't do
that, then you did for some reason that really escapes me. ;-)

Hmmm. I noticed that; I didn't notice that =my= app did it. Trying it
again... hmmm.. curiouser and curiouser. That's a bizzare one! I
guess my app =does= sometimes "oddly truncate subject lines". What does
=your= app do as a reply to your multicolon message (subject line below)?

OT - OT: (was: the OT tag and the Re bug.)

In the above example, a new subject line without any reference to the
topic was created, yet your reply appeared in the thread tree and below
the post to which you responded. IOW, the context was preserved even
though the subject had changed.

That it remained in the same tree is true even of the ordinary bug
posts, which are far more common. But when sorted by subject line, the
ordinary bug posts sort =outside= of the OT slot in the alphabet
(unless the base subject line starts with ot, like "Other pix"). My
bizzare bug preserved the prepend, so it still sorted under OT, where it
belongs.

If the subject line contains the proper reference to the topic (e.g. two
thread tree roots with "Electric Car" in the subject line), then it is not
a big problem to follow the thread.

No. The (minor) problem is for those who wish to screen OT posts which
have been duly labeled for this purpose with the prepend. As soon as
somebody responds with a "bad" reader, a stealth subject is created
which bypasses their "OT" filter. So, sooner or later, the OT prepend
is defeated. This would be true of other prepends too.

Also, at least with OE multiple tree
roots only appear if one is hiding read messages regardless of the subject
line, so I see it as a consequence of the convenience of hiding read
messages rather than a bug in the way the reader works.

Not hiding read messages is more inconvenient than seeing stealth
subject lines. At least for me.

Is there really a downside to avoiding a colon after a prepend?

Jose
--
There are two kinds of people in the world. Those that just want to
know what button to push, and those that want to know what happens when
they push the button.
for Email, make the obvious change in the address.