I don't see that under Messages but under Mailbox there is an option to "Synchronize (my wife's account)". What does that do? I could not find an answer in Mail Help. (Her account is IMAP and mine is POP, if that makes any difference.)
It makes all the difference. POP is an elderly protocol designed to support a single user on a single device. In that environment,
synchronization is a
non-sequitur. IMAP is deigned around the assumption the user will be accessing the account from multiple devices and wants each of them to have all of the same content, so
synchronization is the point. It assures that what your wife sees in Mail on her iPhone is exactly what she would see in Mail on her Mac at home, her PC at the office, and in the webmail interface at an internet café.
