A Unity ID allows you to buy and/or subscribe to Unity products and services, shop in the Asset Store and participate
in the Unity community.
It seems be a bug of Apple, but I don't known it's from XCode 7 or from AppStore.
I faced this issue, what I only can do is download XCode 6.4 and...
Not yet, I use Unity 5.2.3, IsPointerOverGameObject works different with iOS and Standalone, hence we must forget it