【判断当前Selection是否为prefab】
PrefabUtility.GetPrefabParent(target) == null && PrefabUtility.GetPrefabObject(target) != null
参考：file://localhost/Applications/Unity/Unity.app/Contents/Documentation/Documentation/ScriptReference/PrefabUtility.html
判断当前Selection是否为prefab,布布扣,bubuko.com
原文：http://www.cnblogs.com/tekkaman/p/3829767.html