Avoid duplicate emails in the sent folder

[André Rodier]

Hello,

I have a webmail program, that I cannot configure to not save sent
emails in the Sent folder. My emails to the SOGo team don't seem to
reach the mailing list anymore.

So, I have no other choice to think the problem differently, and
_maybe_ use Dovecot to fix this issue. Moreover, I think this could be
useful for other email clients.

First, I have tried to use Sieve, but no success so far:

------
imapsieve_mailbox4_name = * 
  imapsieve_mailbox4_from = Sent
  imapsieve_mailbox4_causes = APPEND, COPY
  imapsieve_mailbox4_after = file:/var/lib/dovecot/sieve/sent-
checks.sieve
------

And this sieve script:

------
Message-ID header.
require [
  "variables",
  "environment",
  "duplicate",
  "imapsieve"
];

[…]

if duplicate :seconds 10 {
   discard;
}
------

Otherwise, can I configure dovecot in a certain way, for instance
create a virtual Sent folder. This would not save the email when
appended, but still returns the list of sent emails ?

But this is not working. Any idea?

Thanks for your help!

André