dovecot - Mar 2010 - INBOX of a shared namespace appears to be always subscribed

In dovecot 1.2.10 I run into the following problem: Our users are  
entitled to share their personal mailboxes. This works. But if user A  
shares any of its mailboxes with user B, then dovecot always reports  
the INBOX of user A as subscribed by user B. No matter whether user B  
really subscribed the INBOX of A, or whether user A permitted user B  
the access to its INBOX. The problem is caused by the repeated call of  
LSUB. Starting with the second call LSUB always shows INBOX as  
subscribed.

To reproduce:
-> telnet imap.xx.yy 143
           1 LOGIN user password
           2 LSUB "" shared/*    => shows shared/UserB/folderXX
           3 LSUB "" shared/*    => shows shared/UserB/INBOX
                                          shared/UserB/folderXX
           4 LSUB "" shared/*    => shows shared/UserB/INBOX
                                          shared/UserB/folderXX

Regards, Holger

I've repeated the tests with LSUB "" *. I think there's a
problem with
setting the namespace prefix.

telnet imap.xx.yy 143
	1 LOGIN user password
	2 LSUB "" *            => shows INBOX
	                                Sent
	                                Trash
	                                folderAA
	                                shared/UserB/folderXX
	3 LSUB "" *            => shows shared/UserB/INBOX
	                                shared/UserB/folderXX
	                                Sent
	                                Trash
	                                folderAA
	4 LSUB "" *            => shows shared/UserB/INBOX
	                                shared/UserB/folderXX
	                                Sent
	                                Trash
	                                folderAA

This behavior is reproducable. Please note that the mailboxes of the 
shared namespace are listed first and the own inbox of the user disappears.

Holger