Minor improvements to graph inspector

MaterialGraphProject/Assets/GraphFramework/SerializableGraph/Editor/Drawing/AbstractGraphInspector.cs

     {
         private readonly TypeMapper m_DataMapper = new TypeMapper(typeof(BasicNodeInspector));
 
-        protected List<INode> m_SelectedNodes;
+        protected List<INode> m_SelectedNodes = new List<INode>();
 
         protected List<AbstractNodeInspector> m_Inspectors = new List<AbstractNodeInspector>();
 
             if (m_GraphAsset == null)
                 return;
 
-            var selectedNodes = m_GraphAsset.drawingData.selection.Select(m_GraphAsset.graph.GetNodeFromGuid).ToList();
-            if (m_SelectedNodes != null && m_Inspectors.All(i => i.node != null) && selectedNodes.SequenceEqual(m_SelectedNodes))
-                return;
-
-            OnSelectionChanged(selectedNodes);
+            using (var selectedNodes = ListPool<INode>.GetDisposable())
+            {
+                selectedNodes.value.AddRange(m_GraphAsset.drawingData.selection.Select(m_GraphAsset.graph.GetNodeFromGuid));
+                if (m_SelectedNodes == null || m_Inspectors.Any(i => i.node == null) || !selectedNodes.value.SequenceEqual(m_SelectedNodes))
+                    OnSelectionChanged(selectedNodes.value);
+            }
-        protected virtual void OnSelectionChanged(List<INode> selectedNodes)
+        protected virtual void OnSelectionChanged(IEnumerable<INode> selectedNodes)
-            m_SelectedNodes = selectedNodes;
+            m_SelectedNodes.Clear();
+            m_SelectedNodes.AddRange(selectedNodes);
             m_Inspectors.Clear();
             foreach (var node in m_SelectedNodes.OfType<SerializableNode>())
             {

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/MaterialGraphInspector.cs

     {
         private bool m_RequiresTime;
 
+        private GUIContent m_Title = new GUIContent();
+
         private AbstractMaterialNode m_PreviewNode;
 
         private AbstractMaterialNode previewNode
                 ForEachChild(m_PreviewNode, (node) => node.onModified -= OnPreviewNodeModified);
                 m_PreviewNode = value;
                 m_NodePreviewPresenter.Initialize(value);
+                m_Title.text = m_PreviewNode.name;
                 m_RequiresTime = false;
                 ForEachChild(m_PreviewNode,
                              (node) =>
         {
             m_NodePreviewPresenter.modificationScope = scope;
             Repaint();
+        }
+
+        protected override void AddTypeMappings(Action<Type, Type> map)
+        {
+            map(typeof(AbstractSurfaceMasterNode), typeof(SurfaceMasterNodeInspector));
         }
 
         public override void OnEnable()
             previewNode = materialGraph.masterNode as AbstractMaterialNode;
         }
 
-        protected override void AddTypeMappings(Action<Type, Type> map)
-        {
-            map(typeof(AbstractSurfaceMasterNode), typeof(SurfaceMasterNodeInspector));
-        }
-
         public override bool HasPreviewGUI()
         {
             return m_PreviewNode != null;
 
         public override GUIContent GetPreviewTitle()
         {
-            return new GUIContent(m_PreviewNode.name);
+            return m_Title;
         }
 
         private void ForEachChild(INode node, Action<INode> action)