runInBackground in Edit Mode

I need to find a method to force Unity Editor in Edit mode to update the scene even if don't have the focus. Application.runInBackground or PlayerSettings.runInBackground works ONLY in Play mode.

Here a gif to explain better, i use Win+E to open another window and test the losing focus.

Any advice? thanks.

Tested with Unity 5.4.3 (any 5.*) - Empty 3D project, only a cube and one static class:

         using UnityEngine;
         using UnityEditor;
         using System.Collections;
         
         [InitializeOnLoad]
         class MyTestEdit
         {
             static MyTestEdit()
             {        
                 EditorApplication.update += OnUpdate; // Only to see if updated in Edit Mode        
         
                 PlayerSettings.runInBackground = true; // Only useful in Play Mode
                 Application.runInBackground = true; // ?
             }
             private static void OnUpdate()
             {
                 GameObject.Find("Cube").transform.Rotate(new Vector3(8, 5, 3));
             }
         }
 

(p.s. gif as link because the image uploader here don't accept it)