Mail not showing unread count for Gmail inbox

Since upgrading to Mavericks I've noticed that I don't get a red circled mail count in the Mail app icon on the dock, or a circled number to the right of the inbox under the left-hand Mailboxes column in Mail app, for my Gmail-linked inbox.

I still get the little number next to the name of the inbox for my other accounts, and all other folders (which some mail is filtered to by rules) show their counts. I've noticed that I get no red mail count in the dock icon for any of my inboxes, even though the option is set.

This is really annoying. I get a lot of mail and I don't like the notification centre sliding in an update every time. The way I check mail, I have filters for a lot which I check via my schedule, and then anything else I can see hasn't been filtered I can deal with. But this way, I have to click into the Gmail inbox just to see if anything new is there. I missed about half-a-day's worth of non-filtered email this morning because I didn't know Mail wasn't telling me about it.

Has anyone else seen this behaviour, and can anything be done about it?