issue with reply to mailing list

[Jon Turney]

On 16/05/2020 20:42, Marco Atzeri via Cygwin wrote:
> On 16.05.2020 20:47, Andrey Repin wrote:
>> Greetings, Marco Atzeri!
>>
>>> it is just me or the cygwin mailing lists post are not
>>> reporting anymore the reply to the list tag ?
>>
>> You seems to have replied to an off-list mail.
>>
>> msgid:0d9b4a1b-05ba-8ab1-3783-c3d1f04f97b7@gmail.com is not found in 
>> my list
>> archive.
> 
> not that the issue.
> That give me the idea that I am not the only one with the issue,
> as I am changing manually the send to address and sometime
> I forget or screw ups.
> 
>>> I am using Thunderbird and the option reply to list is not
>>> offered anymore for any of the cygwin mailing list.
>>
>> Ask Thunderbid, what it expects as an indication of a "list message" ?
>> There's a bunch of "List-xxxx" headers.
> 
> looking in chronological order, I see the problem on the cygwin-apps
> and developer mailing lists from the date of server change.
> 
> The cygwin main list seems to not have the same issue.
> But it can be an issue with Thunderbird as I have impression
> to had the same issue also with it.

Comparing the configuration of the lists, the only significant 
difference I noticed is that cygwin-apps is not configured to add a 
'List-Post' header.

Searching there does seem to be suggestions that the presence of this 
header causes Thunderbird to display a 'Reply to List' button.

I changed the cygwin-apps list configuration to add that.  Let me know 
if that makes things better (or worse!).