Update flag won't go away
My App Store icon in the Dock shows a red "1" indicating an update is ready. When I launch it, the app (OpenGL Extensions 4.0.7) is shown as "Installed", and the installed version matches what is shown in App Store, but I can't make it disappear from the list of apps ready for installation, so my App Store icon is constantly begging for undeserved attention. How do I get rid of that alert?
MacBook Pro, Mac OS X (10.7.4)