When an image doesn't have any flags yet, and you hover over the "Approve" button, a little circle appears that encourages you to click on it. Once someone has Approved an image, if you hover your mouse over the Approve button, you don't get one of those little subtle highlight circles. A few clients have assumed that meant there was no way to unapprove an image (when they just needed to click the Approved flag to unapprove it).
Would it be possible to show that same subtle circular highlight when a user hovers open the green Approved flag?
(The Unapproved flag, and the Favourites star, both have a little highlight when they're checked and you hover over them. Maybe Approved does too, but if it does, it's really feint and hard to see?)