Many thanks, David Shochat, for the tip about Edit Subject. Just
shows how selective one's vision can be. I never use Cc or Bcc so I
never look at that line, and I never saw Edit Subject until you
pointed it out. But this reply is done using Edit Subject, so this
post should be all in order.
And Duncan, I checked each time as I did my other email. It seems to
me that gmail stays with whatever formatting I have set it to. But as
html is the default and one has to use it to do things like embed
pictures and clickable links, most email is conducted in html format
(unless you use a text-only emailer). So I think people revert to
html and then forget to switch when posting to a text only list. I'll
try to remember in future, but can't guarantee it.