How can I get OS X's Mail.app unread numbers to stay current?

Question

I have 5 different Gmail IMAP accounts that I access via Mail.app. The only problem is that the "Unread" counts for each account are always off.

It basically just seems like when I read a message in Mail.app, it doesn't always get marked as read on the Gmail end of things.

How can I keep the numbers in sync?

Answer 1

Right click a folder, "Synchronize [account name]".

Not automatic, not ideal, but it's the only method I've found to do this, as it annoys me too.