[Evolution] IMAP flags

[David Wright <ichbin shadlen org>]

I use evolution (2.2.3) to access an IMAP account. When I answer an
email, or delete it, the local evolution application shows it as
answered or deleted, but it does not set the corresponding flags on the
IMAP server. Then when view my INBOX using a different application, I
don't see which mails have been answered or deleted. How do I make
evolution actually update the flags on the IMAP server?