Gmail has always been a weird service to use via IMAP, because of the way that Gmail’s message organization is designed around labels (where one message can have several labels), whereas IMAP is designed around a traditional folder/mailbox metaphor (where any given message resides in one and only one mailbox at a time). Gmail’s metaphor is superior, but IMAP is the only standard we have for email clients.
As Joe Kissel documents in this piece for TidBITS, the relationship between Apple Mail and Gmail has gotten more complicated than ever in Mavericks. I’m surprised this didn’t boil to the surface during Mavericks’s beta period.
Update 1: I am informed that Apple is aware of the problem, and has a fix for Mail already seeded to employees for testing, and they’re scrambling to ship it as soon as they can.
Update 2: See also: Kissel’s “Why (and How) I’m Saying Goodbye to Gmail” for Macworld.
★ Sunday, 3 November 2013