email threading

[Stasinos Konstantopoulos]

Hi,

When I receive emails from people who use %$#@& outlook there is no
In-Reply-To field even though they have replied to me rather than
compose a new mail (the subject is indeed Re: <prev subj>).

Having failed to persuade them to use a real MUA, I was wondering if
the following exists in mutt: it would somewhat improve the situation
if I could manually force a given message to be added to a thread.

Thanx in advance,

Stasinos