This is an RFE. I've never seen a mail program allow this, but it would be so useful if one did. How many times do you have a single mail thread that gets replied and forwarded ad nauseum until you have 5-10 different threads running through your mailbox all on the same topic and buried among other mail making them difficult to find? It would be incredibly useful to me to be able to designate a mail message as part of the same thread as another message. That way you could select a message select "Reference to another message" (or something) and then click on the message it should be referencing. Then that message and it's sub-messages would be linked to the clicked message and all be considered one thread when viewing a folder in threaded mode. I know next to nothing about the MessageID and References lines to guess as to how this would be done. Anyone want to hazard a guess? Does this sound like something that would be useful?

yeah, it's a cool idea and I've experienced this problem, but I'm moving to the future milestone for now.

Duplicate of bug 36024.

Agree on dupe *** This bug has been marked as a duplicate of 36024 ***