evince

[Garry T. Williams]

On 12-1-13 17:03:07 David wrote:
> That has been discussed to the ends of the universe. He and several
> others and I use the same Mozilla Thunderbird email client. It works for
> me and not them.

I use Kmail and I also set my threading options to try to approximate
threading by paying attention to the Subject header value, date, and
time.  This makes these broken messages sort into the thread I'm
reading.  But...

Without the required headers, there is no way to do proper threading.
It can only come close using Subject header value, date, and time.

> After (limited time and skills here) the only obvious
> difference that I can see is that 'they' use the Fedora packaged
> Thunderbird and I do not. Does this make a difference?

Almost certainly not.  It is a function of the client settings.  Like
I said, you have told your client to use Subject header value, date,
and time to do threading *if* the correct headers are not supplied.

Here's a look at Patrick's headers:

First I snip out the headers supplied by the servers that received his
message.  Then we come to what his message actually supplied:

    Date: Sun, 01 Dec 2013 15:32:17 +0100
    From: "Patrick Dupre" <pdupre at gmx.com>
    Message-ID: <20131201143218.102640 at gmx.com>
    MIME-Version: 1.0
    Subject: Re: evince
    To: "Community support for Fedora users" <users at lists.fedoraproject.org>
    X-Flags: 0001
    X-Mailer: GMX.com Web Mailer
    x-registered: 0
    X-GMX-UID: JS3pcnxJeSEqJ2ux8H0hYYV+IGRvb0CV

Notice that his message didn't include In-Reply-To or References
headers.  BY DEFINITION, this message is a brand new thread.  It
doesn't refer to any previous message.  Patrick broke the thread.

In contrast, here are the headers from the message you wrote and that
I am replying to:

    Message-ID: <529BB21B.2080601 at gmail.com>
    Date: Sun, 01 Dec 2013 17:03:07 -0500
    From: David <dgboles at gmail.com>
    User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64;
	    rv:24.0) Gecko/20100101 Thunderbird/24.1.1
    MIME-Version: 1.0
    To: users at lists.fedoraproject.org
    Subject: Re: evince
    References: <20131201143218.102640 at gmx.com>
	    <529B6DDA.2090701 at gmail.com>	<529B7E01.5050206 at gmail.com>
	    <3476548.tqg5ruCP5g at vfr>
    In-Reply-To: <3476548.tqg5ruCP5g at vfr>
    X-Enigmail-Version: 1.6

Notice that your message properly refers to mine (in its In-Reply-To
header) as what you are replying to and adds all of the other messages
in this "mini-thread" that Patrick started (in its References header).
But there are many more messages in the thread you thought was here.
They are missing because Patrick broke the thread with his message.

Without proper headers, threading is impossible.  The same Subject
header value is *not* a thread identifier.  Only message IDs can be
used for that.

> How the heck
> would I know? I'm the dummy.  :-)

Two ways to know:

1.  Set your client to thread only using proper message headers and to
ignore the Subject header value.

2.  Examine the headers.

As for me, I don't mind the occasional broken thread message so I tell
my client to sort by Subject header value, date, and time, *if* the
proper headers are missing.  I find this works well for me on mailing
lists.  I never do this at my day job.

But this topic got my attention.  It seems that many others set their
clients with similar sorting criteria, but do not know the
implications.

-- 
Garry T. Williams