On Wed, Nov 25, 2020 at 09:30:41AM +1100, Keith Bainbridge wrote: > On Sun, 22 Nov 2020 23:34:56 -0600 David Wright > <deb...@lionunicorn.co.uk> wrote: > > >>> On Mon 23 Nov 2020 at 14:27:36 (+1100), Keith Bainbridge wrote: > >>> > So does htis get a new subject in the list? > > Interesting. I'll try it next time I want to use a comment from one > thread as a separate topic. BUT I wrote a totally new subject line. > Surely that is removing 'Re: '
It's not the Subject: header that matters for thread construction.(*) It's the In-Reply-To: header, which contains the Message-ID:s of your parent message(s). A sufficiently advanced email client (MUA) takes all the messages, with all of their unique Message-ID:s, and all of their In-Reply-To: headers, and constructs a tree in memory, with all of the parent/child relationships laid out explicitly. Then it presents this tree structure to you, however it was programmed to do. (*) Unless you're using Microsoft Outlook or other similar crap.