"1 update available" Mac App Store - already installed
My Mac App Store icon has had a 1-badge for weeks now. When I open the app and go the updates tab, it says "1 update available" and underneath shows the Things 2.0.1 update. I have already installed this; it even says "installed" to the right of the window. How do I get the Mac App Store to recognize that it's installed? Thanks.
MacBook Pro, OS X Mountain Lion (10.8.1), Mac App Store