Hi!

I just experienced a strange thing with threading and imap. For testing purposes I'm syncing a large mailing list with my zoho mail account. When looking at some threads (they are often larger than 50 postings) they look different if I'm looking at them with the web reader, with zoho via imap or with my main account (Google Apps) via imap. (Both with Thunderbird 3.0 on a Mac)

The web reader and imap via Google seems to be (nearly) identically. But via imap I saw strange problems: The subject lines aren't always complete. Sometimes they only consist of the list-tag and the reply sign: "Re: [Listtag]" - but when clicking on the message everything looks fine.

When looking at the thread index I see that several messages are at the wrong place. thy look like they were assorted more like random than like purpose or so ...

I have the feeling that not every imap command is fully implemented by now but that Thunderbird is relying on that. 

Michael

Update: I've found the source of the problem. This problem happens when a header is splitted into multiple lines. For example:

References: <4B197996.5050507@domain.tld>	<4B197FC3.5000600@domain.tld>	<4B1985C8.3090302@domain.tld>	<D0E95420-2643-4EAB-B0CA-F8FB2D3CA8A4@domain.tld>
	<4B28B42B.1070307@domain.tld>

Or:

Subject: Re: [Listtag]
 =?iso-8859-1?q?Some subject?=
 =?iso-8859-1?q?and so on?=

I haven't tested but I guess that the IMAP command FETCH (with HEADER.FIELDS) would only return the first line - not the following lines - although they are part of the header. This would explain the strange threading problems.

Michael