Renaming top level/sub mailboxes

[David Mayo]

When I try to move a top level mailbox to be a sub mailbox, or vice 
versa, the IMAP server returns:

"NO Operation is not supported on mailbox"

eg.

renm user.toplevel user.aa.toplevel
renm user.aa.toplevel user.toplevel

Why is this? Can I get around it other than creating a new mailbox and 
copying the messages over (which loses the \Seen state).

We are running Cyrus 2.3.13.

Regards,


Dave.

David Mayo
Networks/Systems Administrator
University of Bath Computing Services, UK