System.NullReferenceException: (null)
  at (wrapper managed-to-native) UnityEditor.SerializedObject.InternalCreate(UnityEditor.SerializedObject,UnityEngine.Object[],UnityEngine.Object)
  at UnityEditor.SerializedObject..ctor (UnityEngine.Object obj) [0x00013] in /Users/builduser/buildslave/unity/build/Editor/Mono/SerializedObject.cs:10
  at Db.Map.Editor.MapSpawnPointSerializerEditor.OnSceneOpened (UnityEngine.SceneManagement.Scene scene, UnityEditor.SceneManagement.OpenSceneMode mode) [0x0000f] in /Users/nazgul/Documents/Projects/Sources/PopularWars/Assets/Scripts/Db/Map/Editor/MapSpawnPointSerializerEditor.cs:26
  at Db.Map.Editor.MapSpawnPointSerializerEditor..cctor () [0x0004b] in /Users/nazgul/Documents/Projects/Sources/PopularWars/Assets/Scripts/Db/Map/Editor/MapSpawnPointSerializerEditor.cs:20
UnityEditor.EditorAssemblies:ProcessInitializeOnLoadAttributes()