Many users have noticed that the app update icon won’t clear or go away. The updates will stay listed in your update screen. This is so that if you have “Automatic Updates” turned on, you will be able to see what apps have updated and when. If it says “Open” it means it has successfully updated. You will notice that new updates are under a lable called “Available Updates” while updated (Open) apps are listed in groups by the date which they were updated.