[Dovecot] INBOX. namespace

[Brian Candler]

I am trying to configure dovecot-1.2.11 to have the same IMAP namespacing as
courier-imap as per http://wiki.dovecot.org/Migration/Courier, but failing
badly.

I have a test maildir with INBOX and folder 'junk'. Without fiddling with
namespaces, this works fine: there are 91 msgs in INBOX and 2 in junk.

a namespace
* NAMESPACE (("" ".")) NIL NIL
a OK Namespace completed.
a examine INBOX
...
* 91 EXISTS
...
a OK [READ-ONLY] Select completed.
a examine junk
...
* 2 EXISTS
...
a OK [READ-ONLY] Select completed.

Now I make the following addition to dovecot.conf:

namespace private {
   separator = .
   prefix = INBOX.
   inbox = yes
   hidden = no
}

After this the inbox appears to be empty, and I cannot select the junk
folder at all:

a namespace
* NAMESPACE (("INBOX." ".")) NIL NIL
a OK Namespace completed.
a examine INBOX
* FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
* OK [PERMANENTFLAGS ()] Read-only mailbox.
* 0 EXISTS
* 0 RECENT
* OK [UIDVALIDITY 1269605071] UIDs valid
* OK [UIDNEXT 1] Predicted next UID
* OK [HIGHESTMODSEQ 1] Highest
a OK [READ-ONLY] Select completed.
a examine INBOX.junk
* OK [CLOSED] Previous mailbox closed.
a NO Mailbox doesn't exist: junk

Furthermore I can select "INBOX.INBOX" (although that's empty as well)

a examine INBOX.INBOX
* FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
* OK [PERMANENTFLAGS ()] Read-only mailbox.
* 0 EXISTS
* 0 RECENT
* OK [UIDVALIDITY 1269605071] UIDs valid
* OK [UIDNEXT 1] Predicted next UID
* OK [HIGHESTMODSEQ 1] Highest
a OK [READ-ONLY] Select completed.
a examine INBOX.INBOX.INBOX
* OK [CLOSED] Previous mailbox closed.
a NO Mailbox doesn't exist: INBOX.INBOX
a examine junk
a NO Unknown namespace.

Have I misunderstood what I'm supposed to be doing here?

The other relevant setting is:

    mail_location: maildir:%h

but I've not changed this; as I say, this works just fine without meddling
with namespaces.

Many thanks,

Brian.