So far I did not test the issue tracker or bug tracker module intensively, so please forgive me if this question is very basic. I could not find a comprehensive documenation of the issue tracker functionality.

I can easily configure, that emails to e.g. "support@mycompany.com" create new support issues by use of IMAP/IMAPS. This is the same as with Trac (trac.edgewall.com) and its email2trac plugin. I wonder, however, how new ticket creation is prevented, if a conversation with the customer involves multiple emails by their side. In Trac + email2trac, the customer has to put the issue id ("ticket number") into the email subject. This way, the software automatically adds the email to the existing ticket instead of creating a new one. Not a very nice solution, as some customers change the subject and remove the ticket number, but all in all it works fairly well.

The issue tracker module, however, seems to generate a new issue for every email. I could not yet find a way to prevent issue creation and have the successive emails just appended to the existing issue. How does this work?