Created an override for the Lighting debug panel.

Assets/ScriptableRenderPipeline/Core/Debugging/DebugItemHandler.cs

         // Method that will create UI items for runtime debug menu.
         public abstract DebugItemUI BuildGUI(GameObject parent);
         // Method users need to override for editor specific UI
-        public abstract bool OnEditorGUI();
+        public abstract bool OnEditorGUIImpl();
+        public void OnEditorGUI()
+        {
+            if(OnEditorGUIImpl())
+            {
+                DebugMenuUI.changed = true;
+            }
+        }
+
         // Method users need to override for specific serialization of custom types.
         public abstract DebugItemState CreateDebugItemState();
     }
             return false;
         }
 
-        public override bool OnEditorGUI()
+        public override bool OnEditorGUIImpl()
         {
             Initialize();
 
         }
 
 #if UNITY_EDITOR
-        public override bool OnEditorGUI()
+        public override bool OnEditorGUIImpl()
         {
             Initialize();
 
         }
 
 #if UNITY_EDITOR
-        public override bool OnEditorGUI()
+        public override bool OnEditorGUIImpl()
         {
             Initialize();
 

Assets/ScriptableRenderPipeline/Core/Debugging/DebugMenuManager.cs

         private void AddDebugPanel(DebugPanel panel)
         {
             m_DebugPanels.Add(panel);
+            m_DebugMenuUI.AddDebugPanel(panel);
         }
 
         public void AddDebugItem<DebugPanelType, DebugItemType>(string name, Func<object> getter, Action<object> setter = null, bool dynamicDisplay = false, DebugItemHandler handler = null) where DebugPanelType : DebugPanel

Assets/ScriptableRenderPipeline/Core/Debugging/DebugMenuUI.cs

         public bool isEnabled           { get { return m_Enabled; } }
         public int  activePanelIndex    { get { return m_ActivePanelIndex; } set { m_ActivePanelIndex = value; } }
 
+        static bool         s_UIChanged = false;
+        static public bool  changed     { get { return s_UIChanged; } set { s_UIChanged = value; } }
+
         public DebugMenuUI(DebugMenuManager manager)
         {
             m_DebugMenuManager = manager;
             m_DebugMenuManager.GetPersistentDebugPanel().panelUI.BuildGUI(m_PersistentPanelLayout);
             m_PersistentDebugPanelUI = m_DebugMenuManager.GetPersistentDebugPanel().panelUI;
 
-            m_DebugPanelUIs.Clear();
-                m_DebugPanelUIs.Add(m_DebugMenuManager.GetDebugPanel(i).panelUI);
+        public void AddDebugPanel(DebugPanel panel)
+        {
+            m_DebugPanelUIs.Add(panel.panelUI);
+        }
+
+            s_UIChanged = false;
+            if(s_UIChanged)
+            {
+                UnityEditorInternal.InternalEditorUtility.RepaintAllViews();
+            }
         }
 #endif
 

Assets/ScriptableRenderPipeline/Core/Debugging/DebugPanel.cs

             }
 
             newItem.SetDebugItemState(itemState);
-            //m_DebugPanelUI.RebuildGUI();
         }
     }
 
         {
             m_DebugPanelUI = new DebugPanelUIClass();
             m_DebugPanelUI.SetDebugPanel(this);
-        }
-    }
-
-    public class LightingDebugPanel
-        : DebugPanel<DebugPanelUI>
-    {
-        public LightingDebugPanel()
-            : base("Lighting")
-        {
         }
     }
 }

Assets/ScriptableRenderPipeline/Core/Debugging/DebugPanelUI.cs

             menuVLRectTransform.anchorMin = new Vector2(0.0f, 0.0f);
             menuVLRectTransform.anchorMax = new Vector2(1.0f, 1.0f);
 
-            DebugMenuUI.CreateTextElement(string.Format("{0} Title", m_DebugPanel.name), m_DebugPanel.name, 14, TextAnchor.MiddleLeft, m_Root);
-
+            for (int i = 0; i < m_Root.transform.childCount; ++i)
+            {
+                Object.DestroyImmediate(m_Root.transform.GetChild(i).gameObject);
+            }
             BuildGUIImpl(m_Root);
         }
 
+            DebugMenuUI.CreateTextElement(string.Format("{0} Title", m_DebugPanel.name), m_DebugPanel.name, 14, TextAnchor.MiddleLeft, m_Root);
+
             m_ItemsUI.Clear();
             for (int i = 0; i < m_DebugPanel.itemCount; i++)
             {
         {
             using (new UnityEditor.EditorGUILayout.VerticalScope())
             {
-                bool needRepaint = false;
-                    needRepaint = needRepaint || m_DebugPanel.GetDebugItem(i).handler.OnEditorGUI();
+                    m_DebugPanel.GetDebugItem(i).handler.OnEditorGUI();
-
-                if (needRepaint)
-                    UnityEditorInternal.InternalEditorUtility.RepaintAllViews();
             }
         }
 #endif

Assets/ScriptableRenderPipeline/Core/Debugging/Editor/DebugMenuEditor.cs

             // Contrary to the menu in the player, here we always render the menu wether it's enabled or not. This is a separate window so user can manage it however they want.
             EditorGUI.BeginChangeCheck();
             DebugMenuUI debugMenuUI = m_DebugMenu.menuUI;
-            int debugMenuCount = debugMenuUI.panelCount;
+            int debugMenuCount = m_DebugMenu.panelCount;
             int activePanelIndex = debugMenuUI.activePanelIndex;
             using (new EditorGUILayout.HorizontalScope())
             {

Assets/ScriptableRenderPipeline/HDRenderPipeline/Debug/LightingDebugPanel.cs

+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine;
+
+#if UNITY_EDITOR
+using UnityEditor;
+#endif
+
+namespace UnityEngine.Experimental.Rendering.HDPipeline
+{
+    public class LightingDebugPanelUI
+        : DebugPanelUI
+    {
+#if UNITY_EDITOR
+        public override void OnEditorGUI()
+        {
+            using (new UnityEditor.EditorGUILayout.VerticalScope())
+            {
+                m_DebugPanel.GetDebugItem("Enable Shadows").handler.OnEditorGUI();
+
+                DebugItem shadowDebug = m_DebugPanel.GetDebugItem("Shadow Debug Mode");
+                shadowDebug.handler.OnEditorGUI();
+                if ((ShadowMapDebugMode)shadowDebug.GetValue() == ShadowMapDebugMode.VisualizeShadowMap)
+                {
+                    EditorGUI.indentLevel++;
+                    m_DebugPanel.GetDebugItem("Shadow Map Index").handler.OnEditorGUI();
+                    EditorGUI.indentLevel--;
+                }
+                DebugItem lightingDebugModeItem = m_DebugPanel.GetDebugItem("Lighting Debug Mode");
+                lightingDebugModeItem.handler.OnEditorGUI();
+                if ((DebugLightingMode)lightingDebugModeItem.GetValue() == DebugLightingMode.SpecularLighting)
+                {
+                    EditorGUI.indentLevel++;
+                    DebugItem overrideSmoothnessItem = m_DebugPanel.GetDebugItem("Override Smoothness");
+                    overrideSmoothnessItem.handler.OnEditorGUI();
+                    if ((bool)overrideSmoothnessItem.GetValue())
+                    {
+                        m_DebugPanel.GetDebugItem("Override Smoothness Value").handler.OnEditorGUI();
+                    }
+                    EditorGUI.indentLevel--;
+                }
+                else if ((DebugLightingMode)lightingDebugModeItem.GetValue() == DebugLightingMode.DiffuseLighting)
+                {
+                    EditorGUI.indentLevel++;
+                    m_DebugPanel.GetDebugItem("Debug Lighting Albedo").handler.OnEditorGUI();
+                    EditorGUI.indentLevel--;
+                }
+
+                DebugItem displaySkyReflecItem = m_DebugPanel.GetDebugItem("Display Sky Reflection");
+                displaySkyReflecItem.handler.OnEditorGUI();
+                if ((bool)displaySkyReflecItem.GetValue())
+                {
+                    EditorGUI.indentLevel++;
+                    m_DebugPanel.GetDebugItem("Sky Reflection Mipmap").handler.OnEditorGUI();
+                    EditorGUI.indentLevel--;
+                }
+            }
+        }
+#endif
+    }
+
+    public class LightingDebugPanel
+        : DebugPanel<LightingDebugPanelUI>
+    {
+        public LightingDebugPanel()
+            : base("Lighting")
+        {
+        }
+    }
+}

Assets/ScriptableRenderPipeline/HDRenderPipeline/Debug/LightingDebugPanel.cs.meta

+fileFormatVersion: 2
+guid: 19cc6398a661be547848eb23d58699cf
+timeCreated: 1495638676
+licenseType: Pro
+MonoImporter:
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: