[Dovecot] problems upgrade 2.0 - 2.1 virtual inbox broken / special use namespace

[Robert Schetterer]

Hi Timo

the virtual setup got broke after update to 2.1
( its still working under 2.0 ) on other loadbalanced server

namespace default {
  separator = /
  prefix = ""
  list = yes
  subscriptions = yes
  hidden = no
}

namespace virtual {
  prefix = "virtual/"
  separator = /
  location = virtual:/etc/dovecot/virtual:LAYOUT=maildir++:INDEX=~/virtual
  hidden = yes
  list = no
  subscriptions= no
}

namespace real {
  prefix = "RealMails/"
  separator = /
  list = no
  hidden = yes
}


after upgrade  i have

Error: Couldn't open INBOX: Virtual mailbox open failed because of
mailbox <hidden>/RealMails/: Invalid mailbox name

---------------------

also

i wanted
 to include

namespace inbox {

  #mailbox name {
    # auto=create will automatically create this mailbox.
    # auto=subscribe will both create and subscribe to the mailbox.
    #auto = no

    # Space separated list of IMAP SPECIAL-USE attributes as specified by
    # RFC 6154: \All \Archive \Drafts \Flagged \Junk \Sent \Trash
    #special_use =
  #}

  # These mailboxes are widely used and could perhaps be created
automatically:
  mailbox Drafts {
    special_use = \Drafts
  }
  mailbox Junk {
    special_use = \Junk
  }
  mailbox Trash {
    special_use = \Trash
  }

  # For \Sent mailboxes there are two widely used names. We'll mark both of
  # them as \Sent. User typically deletes one of them if duplicates are
created.
  mailbox Sent {
    special_use = \Sent
  }
  mailbox "Sent Messages" {
    special_use = \Sent
  }

  # If you have a virtual "All messages" mailbox:
  mailbox virtual/All {
    special_use = \All
  }

  # If you have a virtual "Flagged" mailbox:
  mailbox virtual/Flagged {
    special_use = \Flagged
  }
}

but i found no working namespace combination with virtual
-- 
Best Regards

MfG Robert Schetterer

Germany/Munich/Bavaria