Automatically subscribe to the INBOX folder

[glts]

Hello,

I am using the ‘auto = subscribe’ feature in the mailbox configuration
section in the usual fashion (as shown in conf.d/15-mailboxes.conf):

namespace inbox {
  inbox = yes
  mailbox Drafts {
    special_use = \Drafts
    auto = subscribe
  }
  ...
}

When I connect to an account with the Thunderbird mail client, those
mailboxes/folders get autocreated and autosubscribed. Good!

INBOX, however, does not get subscribed to automatically. When I look at
the account’s subscriptions in Thunderbird, all folders are subscribed,
except INBOX.

How can I enable autosubscribe for the INBOX folder (like the other
folders)? Is there an option for this? This is in Dovecot 2.2.22.

Cheers,
David