"NullReferenceException: Object reference not set to an instance of an object" error appears in the console when creating new “Sprite Shape Profile”

Preconditions:
Project Files : Download the attached zip folder containing the SpriteShape feature. The latest is available on gitlab. Link: https://gitlab.internal.unity3d.com/2d/2d-spriteshape

Steps to Reproduce:
1. Create a new Project in Unity3D
2. Drag and Drop the "2d-spriteshape-master" folder into the Assets folder of the project
3. Click on Assets Menu > Create > Sprite Shape Profile > Profile.

Console will show the error.

Stack trace on Console is :
NullReferenceException: Object reference not set to an instance of an object
UnityEditor.U2D.EditorGUIReflection.GetCurrentInspectorWindow () (at Assets/2d-spriteshape-master/Editor/EditorGUIReflection.cs:62)
UnityEditor.U2D.SpriteShapeEditor.OnInspectorGUI () (at Assets/2d-spriteshape-master/Editor/SpriteShapeEditor.cs:167)
UnityEditor.InspectorWindow.DrawEditor (UnityEditor.Editor[] editors, Int32 editorIndex, Boolean rebuildOptimizedGUIBlock, System.Boolean& showImportedObjectBarNext, UnityEngine.Rect& importedObjectBarRect) (at /Users/builduser/buildslave/unity/build/Editor/Mono/Inspector/InspectorWindow.cs:1299)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)

Notes:
- Appears on both Mac and Windows
- Appears always

Frequency: 5/5

Reproduced on: 2018.1.0a5

Regression introduced on: 2018.1.0a5

Works fine on: 2018.1.0a4, 2017.3.0b9

License type: Pro