Shared mailboxes nightmare (for me :-( )

[Felix Rubio Dalmau]

Hi everybody,

I am honestly desperate: I have spent/invested the whole day in trying to set a 
shared mailbox, with quite partial success. The INBOX is merged with the top 
level mailbox, and there are many more folders. To give an idea, for the shared 
account shared...@domain.org, this is how looks the folder structure:

sharedacc
  |-folderA
  |-folderB
  \-folderC

in the account for us...@domain.org, I see the following:

usera
  |-folderD
  |-folderE
  |-folderF
  \-shared
     \-sharedacc

So, I do not get to see folderA, folderB, folderC, etc.

My configuration is:

    # 2.2.25 (7be1766): /etc/dovecot/dovecot.conf
    # Pigeonhole version 0.4.14 (099a97c)
    # OS: Linux 4.5.4-0 x86_64 Debian stretch/sid zfs

    mail_plugins = zlib expire acl

    plugin {
    acl = vfile
    acl_shared_dict = proxy::acl
    }

    dict {
    acl = mysql:/etc/dovecot/dovecot-dict-sql.conf.ext
    }

    namespace {
    list = children
    location = 
mdbox:/mnt/vmail/%%d/%%n:INDEXPVT=/mnt/vmail/indexes/shared/%%d/%%n
    prefix = shared/%%n/
    separator = /
    subscriptions = yes
    type = shared
    }

    protocol lmtp {
    mail_plugins = zlib expire acl sieve
    }

    protocol imap {
    mail_plugins = zlib expire acl antispam imap_acl
    }

the files I have one the account for sharedacc are:
    sharedacc
      |-dovecot-acl
      |-dovecot-acl-list
      \-mailboxes
          |-dovecot-acl
          |-folderA
          |   \-dbox-Mails
          |       \-dovecot-acl
          |-folderB
          |   \-dbox-Mails
          |       \-dovecot-acl
          \-folderC
              \-dbox-Mails
                  \-dovecot-acl

In dovecot-acl-list I have the following contents:
    1474920778 folderA
    1474920778 folderB
    1474920778 folderC

and in every dovecot-acl, I have:
    user=us...@domain.org  akxeilprwts

All the files on the filesystem are owned by the same vmail user.
What is strange is that I can see all these folderA, folderB, folderC in 
roundcube, and I can click to subscribe to them. However, when I go back to the 
general view, the subscriptions have been reset and I see only sharedacc, 
without a thing inside. Finally, in kmail I can see the subscribed folders 
without a problem (??!)

Can please somebody help me?