iMac App Store showing 1 update avaialable

My iMac App Store is showing that there is an update available for my copy of iPhoto Rev. 9.1.2. Indeed Ver. 9.1.3 is available. When I hit update the App Store tells me that "iPhoto" is already installed on the computer and to go to "Software Update" and to see if any of my software has any updates. I go to "Software Update" and that states all of my software is up to date. BUT I still have the notification showing on the icon of the App Store and it continues to tell and update is available starting this go around again. Any way to just clear the App Store Update?