NullReferenceException if user Packs Preview after multi-selecting assets to pack in a view-locked atlas

1. Import 2 sprites
2. In Assets, right click > Create > Sprite Atlas
3. Lock atlas view in Inspector
4. Multi-select both sprites and drag them into the "Objects for Packing" area
5. Press "Pack Preview"

Expected: No error
Observed: NullReferenceException

Occurring on: 2017.1.0a5 (first appearance of Sprite Atlas) until 2017.2.0a4 (current latest trunk)

NullReferenceException: Object reference not set to an instance of an object
UnityEditor.InspectorWindow.GetEditorsWithPreviews (UnityEditor.Editor[] editors) (at /Users/weswong/Work/trunk/unity/Editor/Mono/Inspector/InspectorWindow.cs:515)
UnityEditor.InspectorWindow.DrawPreviewAndLabels () (at /Users/weswong/Work/trunk/unity/Editor/Mono/Inspector/InspectorWindow.cs:612)
UnityEditor.InspectorWindow.OnGUI () (at /Users/weswong/Work/trunk/unity/Editor/Mono/Inspector/InspectorWindow.cs:398)
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:222)
Rethrow as TargetInvocationException: Exception has been thrown by the target of an invocation.
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:232)
System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MethodBase.cs:115)
UnityEditor.HostView.Invoke (System.String methodName, System.Object obj) (at /Users/weswong/Work/trunk/unity/Editor/Mono/HostView.cs:283)
UnityEditor.HostView.Invoke (System.String methodName) (at /Users/weswong/Work/trunk/unity/Editor/Mono/HostView.cs:276)
UnityEditor.HostView.InvokeOnGUI (Rect onGUIPosition) (at /Users/weswong/Work/trunk/unity/Editor/Mono/HostView.cs:243)