[Dovecot] outlook 2007 can't see public folders more than 1 deep

[Frank Cusack]

dovecot-1.2.9

I have a public folder using ACLs to determine who can access it.

namespace public {
  separator = /
  prefix = shared/
  location = maildir:/var/maildir/shared
  subscriptions = no
}

Outlook 2007 can't see any folders except at the top level.  It can
create them just fine, but can't see them after quit and restart.

For example, I can create the folder shared/foo/bar but on restart
outlook only sees foo as a folder without subfolders (no + to expand it)
and doesn't see bar anymore.  In fact I can delete the folder foo
in outlook and then BOTH .foo and .foo.bar directories are removed
on the server.

When you click on foo, the error message in the mail pane is "Cannot
display the folder.  The folder 'foo' cannot contain items.  This is
most likely a limitation of your IMAP server.  In order to create a
folder that can contain items, be sure not to append '/' to its name
as you create it."

-frank