Steps to reproduce:

1. Open attached project
2. Open scene "scene1"
3. Notice NullReferenceException in console:
NullReferenceException: Object reference not set to an instance of an object
UnityEditor.Handles.DoPositionHandle (Vector3 position, Quaternion rotation) (at C:/buildslave/unity/build/Editor/Mono/EditorHandles/PositionHandle.cs:30)

Note: If exception isn't thrown right away then in hierarchy select Main Camera and move it

Reproduced with: 5.1.4f1, 5.2.4f1, 5.3.2p4, 5.4.0b7