I forgot to specify:

Windows 10 1903 x64 Thunderbird 60.9.0 32 bit

It could be an indexing issue, so I suggest right-clicking the folder, Properties, Repair Folder, to rebuild the index msf file. It could also be that some senders use email programs that don't insert the relevant headers.

http://kb.mozillazine.org/Stop_threading_by_subject

thank you for the reply, but this is not the case. It seemed that, after a reindexing, things were better, but it's not so. After receiving new mails, some of them are again in the wrong place. Is the grouping routine used for mails the same that is used for newsgroups? It would be interesting to know because if it is exactly the same routine, then we are certain that there is no software bug and the problem lies elsewhere. But if the mail routine is different than the news routine, then this is a strong symptom that something could be wrong in the code.

How can I know, examining the mail header, that it is not correct and that some elements of it are missing?

Thank you. Sal

Start by looking at the references header information. I see a distressingly large number of mail clients that simply do not manage to get it right, As with newsgroups, no references just breaks threading.

Matt said

Start by looking at the references header information. I see a distressingly large number of mail clients that simply do not manage to get it right, As with newsgroups, no references just breaks threading.

Matt,

I've taken one message as example. This is the first reply to my father message, and this reply is, of course, out of the thread (see image). Following, the "References" parts found in the header of the first reply:

To: <DXLab@groups.io> References: <AM0PR04MB7153E765990986122C142AFF83B10@AM0PR04MB7153.eurprd04.prod.outlook.com> In-Reply-To: <AM0PR04MB7153E765990986122C142AFF83B10@AM0PR04MB7153.eurprd04.prod.outlook.com>

Please, notice that messages following the first reply stay in thread.

The father message has been posted by me.

Sal

I have a theory as to what might be occuring.

re :The father message has been posted by me. So this first email in conversation, was a sent mail. Usually this email would only be in the 'Sent' folder. Are you saying you sent an email to some people and included yourself to be sent a copy, hence why you have 'received' the email and it is shown in same folder as your incoming threaded responses?

• [DX Lab] RAT [DXKeeper] date 11-09-19 22:30

and these were subsequent 'received' - sent to you by someone else - incoming emails as a result of your initial email. Starting with....

• Re: [DX Lab] RAT [DXKeeper] date 11-09-19 23.05

which you replied to as indicated by the arrow. But your reply is not actually shown because it is in the 'Sent' folder then you received two reply responses as shown.

The point I'm saying is this. The threaded replies are replies to original sent email which you sent to others, but not a reply to the initial 'copy' you also sent to yourself. Hence why the copy in Inbox/folder as indicated as 'Father message' which you originally sent does not show as threaded. No one has replied to 'your copy' of the email.

What do you see if you right click on :

• Re: [DX Lab] RAT [DXKeeper] date 11-09-19 23.05

and select 'Open message in conversation' This amalgamates all messages sent and received in the entire conversation. It is an ideal method of viewing a single uncluttered conversation that includes all comments. Do you see your original 'sent' message - this would be the copy of sent message located in 'Sent' folder - (not the copy called 'Father message' you sent to yourself in Inbox) - followed by all reponses and all are threaded?

If what I've indicated is true: Suggestion: Do not send copies of emails you send to yourself ( You already have a copy in the 'Sent' folder) as this may be the reason you are seeing apparently disjoined threading when inreality the threading is correct.

hello,

let's see things in order:

• this is a mailing list
• the so called "father message" is not the message that I originally wrote and that I could have moved from Sent folder to mailing list folder
• this mailing list automatically send to subscribers "all messages", including those written by the subscriber himself/herself, so the father message is arrived together with the others. In fact I usually delete the message that I wrote and that is in the Sent folder because I will receive it together with all the other messages. This is exactly the same behaviour found in newsgroups that are, more or less, another kind of mailing list, in which subscriber receives also messages written by himself/herself.

> What do you see if you right click on :

All the following messages are shown, but not the father message.

> Do you see your original 'sent' message

No, because I immediatly delete it after sending, being it not necessary because my message is resent by the mailing list and so it should be included in the conversation.

Anyway my father message's header contains this:

X-Orig-Message-Id: <AM0PR04MB7153E765990986122C142AFF83B10@AM0PR04MB7153.eurprd04.prod.outlook.com>

This value is equal to the References field value of the first reply:

References: <AM0PR04MB7153E765990986122C142AFF83B10@AM0PR04MB7153.eurprd04.prod.outlook.com>

So they should both be shown in thread, right?

Moreover, my father message's header contains also this value that is not found in the first reply:

Thread-Index: AQHVaN+8kuPPG1YzLEODrsz3UYJ5Ow==

Sal

re :the so called "father message" is not the message that I originally wrote But you are the original creator of that email.

re: and that I could have moved from Sent folder to mailing list folder No I never suggested you had moved it from one folder to another. I stated you had received a copy of an email you had sent - which you acknowledge as true. I wondered if you had deliberately sent a copy to yourself , but in fact you did get a copy of orignal but it was via a mailing list mechanism.

re :I immediatly delete it after sending, being it not necessary because my message is resent by the mailing list. Suggest you keep it so you can test the theory. It not doing any harm to use it as a test.

At least we now understand the setup.

Please check: Are you discovering that for mailing list conversation threads which appear broken, in all cases, they do not include emails you wrote/composed - all your initial emails (which you receive in inbox due to mailing list practise) are not being included in threads and the result is breaking up threading?

Are you discovering that any email you reply to mailing list resulting in a copy being sent to you, does not get correctly positioned in a thread and so makes it look like the threading is broken?

I'm looking at the images and it seems to me that only your comments which you receive back as incoming mail as not being included in the threading. Is that true ?

> Are you discovering that for mailing list conversation threads > which appear broken, in all cases, they do not include emails > you wrote/composed

yes (if I have understood your question correctly).

> Are you discovering that any email you reply to mailing list > resulting in a copy being sent to you, does not get correctly > positioned in a thread and so makes it look like the threading > is broken?

no, it seems to happen only with the message with which I have initiated the thread.

> I'm looking at the images and it seems to me that only your > comments which you receive back as incoming mail as not > being included in the threading

not exactly. It seems to happen only with the message with which I have initiated the thread. Following replies written by me seems to go in the thread correctly.

Now let's see the attached image. It is another mailing list, but the image shows a broken thread in which I haven't participated, that's to say, there are no messages written by me.

The thread begins with lowest highlighted message, but you can see another group of three messages above, completely out of the thread and their dates are subsequent to thread's first message. I repeat: there are no messages coming from me in this thread.

Salvatore

mmmh, sorry, I've seen only now that the subject of the three messages outside of the thread has been modified, but I suppose that the reference value should remain the same, or not?

There is an article here that discussed some setting in the Thunderbird config editor that you can use to modify how threading works.

I think with judicious use you will get to the result you are seeking. The defaults do not suit everyone.

Different subject - similar, but different hence separate threading.

Under normal email/reply/threading, the initial email, if created by you, would never be in the Inbox, so the broken threading situation would never occur. There would only be the copy in the 'Sent' folder and all sent and received emails would only display as complete conversation in the 'Open message in conversation' window.

Next time you start a question in the Mailing List, suggest you do not delete the saved 'Sent' copy, so you can test whether that saved sent email is shown in the threading when you 'open message in conversation'. That would be useful to know.

Thanks for providing info, we have nailed down the anomaly to only being emails initiated by you in which you have also been sent a copy to your Inbox and that copy is not being included in the threading. This is very specific.

As I'm not certain what if any addon extensions you use eg: Conversations or whether they are causing any conflict - Q: Do you see the same issue if you restart Thunderbird in Safe mode?

Normally, I would say, that email does not have replies threaded because that copy in Inbox has not had any replies or subsequent responses to that particular email. It is a stand alone non responded email. But as you say, it is part of a mailing list situation, so I can see how you would expect threading to occur.

Threading example source code header I've seen: Message ID: <letter numbers etc> being same <letter numbers etc> as replies which would have a header : In-Reply-to: <letter numbers etc>

Matt and sfhowes: Now that the issue has been identified, can you offer more insight as to what could be occuring ? I have limited experience when it comes to mailing list scenarios.

hello,

> Different subject - similar, but different hence separate threading

shouldn't the reference value be used anyway and so be in thread even with a different subject?

> As I'm not certain what if any addon extensions you > use eg: Conversations

no, the only installed extensions are those shown in the image.

> Q: Do you see the same issue if you restart Thunderbird in Safe mode?

yes, exactly the same issue.

> But as you say, it is part of a mailing list situation, so > I can see how you would expect threading to occur.

yes, also because the news reader behaviour is that (initiating message is ALWAYS threaded), and I expected the mail reader to be the same. But I'd like very much to see the same behaviour in Inbox where, for example, I initiate a thread sending an e-mail to my sister and then I move my original message from Sent to Inbox. Afterwards my sister replies, I reply to her reply and so on, and I'd like to see all messages threaded, including my initiating message. Maybe and idea for a future release of Thunderbird?

Remember that my knowledge is very limited.

Thank you. Salvatore

Matt offered a good link:

One of the options may offer what you are looking for so it is worth giving it a try. mail.thread_without_re will thread based on the subject even if there is no Re: in the subject. It defaults to false

'Menu icon > Options > Advanced > 'General' tab click on 'Config Editor' button In search type: without look for this line : mail.thread_without_re double click on that line to toggle the value from default 'false' to 'True' close window - top right X click on 'OK'

Restart Thunderbird. Check the threads. Please report back on results.

hello,

> look for this line : mail.thread_without_re ..... > Please report back on results

no changes. Thread remains broken exactly as before. I'm inspecting the thread where I have never posted a message.

Salvatore