How to keep trace of a message thread

Hoy would you keep trace of an email message thread.

What I mean is, when you send an email people replies to it, or forwards it…

What is the common way to see that emails are replies or forwards?

I know there is a $MessageID but I saw that in practice they aren’t the same…

Thanks

Subject: How to keep trace of a message thread

Thanks, however this view uses “parent-responses” and for external emails this hierarchy does not exist…

Subject: How to keep trace of a message thread

The common way, as you ask, is to use the Mail Threads view built into the mailfile outline.