Setting per-mailbox identity in 2.2.0

[Willem Riede <wriede riede org>]

When I bring up a mailbox property window, it has a field for identity,
with (No identity set) as its value. Next to it is a "change" button.
Click that, and the identity selector window pops up. However, that
window is inactive. Cannot select an identity, nothing happens. Cannot
cancel or exit the identity selection window by clicking those buttons,
nor close through the window manager. Both the property and the identiry
selection window close when I click the cancel button in the property
window. In case it matters, this is with a IMAP folder, served by Dovecot.

Any suggestions? Thanks, Willem Riede.