Some major email providers do not support threading based on in-reply-to headers, and instead use the subject. This should be possible to alter in _message_alter. It could be a setting, though I'm not sure it needs to be.

Comments

Ian Ward’s picture

Ian Ward commented

This issue supersedes http://drupal.org/node/255384, which I just closed.

Ian Ward’s picture

Ian Ward commented
Status: Active » Fixed

I've applied a patch which adds a setting to alter message subjects along these lines. This made threading work for me in gmail.

greggles’s picture

greggles
he/him
Primary language English
Location Denver, Colorado, USA
commented

A little late, but in my testing this works great for me as well. Thanks!

Status: Fixed » Closed (fixed)

Automatically closed -- issue fixed for 2 weeks with no activity.