[Dovecot] Cannot subscribe to shared folders

[Lukas Haase]

Hi,

I am unable to subscribe to shared folders with Thunderbird although 
everything seems to be correct (dovecot 1.2).

What does not work? I click "Subscribe..." in Thunderbird. The shared 
mailboxes are listed, all with [ ] (no checkbox). Therefore I mark them 
[x], click "subscribe" and "OK". However, the folders do not appear in 
the folder tree. Furthermore, when I again click "Subscribe..." the 
folders do NOT have the mark [x] any more. This happens on different 
computers with *new* profiles.

My configuration is the following (maybe that is the problem?!):

namespace private {
    separator = .
    prefix =.
    inbox = no
    list = no
    hidden = yes
    location = maildir:~/Maildir-root
    subscriptions = yes
}

namespace private {
    separator = .
    prefix = INBOX.
    inbox = yes
    subscriptions = yes
}

namespace public {
    separator = .
    prefix = Shared.
    location = maildir:/var/mail/shared:INDEX=~/Maildir/shared:LAYOUT=fs
    subscriptions = no
}

The folder /var/mail/shared has appropriate permissions/form:
* Owner: $user:mailuser (all users are member of "mailuser")
* All files 0660, all folders 0770
* There exists a dovecot-shared in every folder
* There exists a dovecot-acl in each folder where each user has the 
permissions "lrwstie"

I switched on "mail_debug = yes" but no messages.

However, the file ~/Maildir-root/subscriptions contains the subscribed 
folders:

Shared.Group1
Shared.Group2
Shared.Group1/Test

Furthermore, I switched on rawlog. Everything seems to be OK as well:

.in-file:
2 subscribe "Shared.Group1"
3 lsub "" "INBOX.*"
5 lsub "" "Shared.*"
6 list "" "INBOX"

.out-file:
2 OK Subscribe completed.
[...]

I am pretty sure it already worked. But it stopped working. Does anybody 
have a hint what could be the problem?

Regards,
Luke