User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.5) Gecko/20031007 Firebird/0.7 Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.5) Gecko/20031007 Firebird/0.7 Currently, it seems threads are defined from the "Subject" field of mails, which often produce wrong results. Many mails are displayed as beeing in the same thread, while the "In-Reply-To" and "References" headers clearly state that they are NOT. Reproducible: Always Steps to Reproduce: 1. Just select thread view in a large mailbox... 2. Have two++ mails that have the same Subject (i.e "Hello") 3. Observe that they appear in the same thread regardless of mail-header info. Actual Results: The problem described above occured Expected Results: Threading should be based on the mail headers "In-Reply-To" and "References". It should at least be an option to thread by these rules instead of the Subject field.

related to bug 180299 ? There's a patch there... not sure if it bitrotted...

I don't think it is. This is an extremely irritating bug/feature. It would be very nice to have an option to only have it sort by references/in reply to headers - rather than subjects as well.

Also happens Thunderbird in Windows (0.7+ 20040629), please change OS :) Please fix, this is reeeeally annoying on my .talk newsgroup where there are many posts in different threads which start with "Good morning" or suchlike and all get lumped into the same thread.

OS -> All

*** Bug 253344 has been marked as a duplicate of this bug. ***

*** This bug has been marked as a duplicate of 164115 ***