Apply on array

ScriptableRenderPipeline/HDRenderPipeline/HDRP/HDRenderPipeline.cs

-using System.Collections.Generic;
+using System.Collections;
+using System.Collections.Generic;
 using UnityEngine.Rendering;
 using UnityEngine.Experimental.Rendering;
 using System;
 
         static public void SetupDrawMode()
         {
-            SceneView sceneView = EditorWindow.GetWindow<SceneView>();
-            sceneView.onValidateCameraMode += RejectDrawMode;
+            ArrayList sceneViewArray = SceneView.sceneViews;
+            foreach (SceneView sceneView in sceneViewArray)
+                sceneView.onValidateCameraMode += RejectDrawMode;
-            SceneView sceneView = EditorWindow.GetWindow<SceneView>();
-            sceneView.onValidateCameraMode -= RejectDrawMode;
+            ArrayList sceneViewArray = SceneView.sceneViews;
+            foreach (SceneView sceneView in sceneViewArray)
+                sceneView.onValidateCameraMode -= RejectDrawMode;
         }
     }
 #endif