diff --git a/Scripts/Editor/NodeEditorGUI.cs b/Scripts/Editor/NodeEditorGUI.cs
index 7447b8a..a2908b6 100644
--- a/Scripts/Editor/NodeEditorGUI.cs
+++ b/Scripts/Editor/NodeEditorGUI.cs
@@ -441,14 +441,10 @@ namespace XNodeEditor {
         }
 
         private void DrawTooltip() {
-            if (hoveredPort != null && NodeEditorPreferences.GetSettings().portTooltips) {
-                Type type = hoveredPort.ValueType;
-                GUIContent content = new GUIContent();
-                content.text = type.PrettyName();
-                if (hoveredPort.IsOutput) {
-                    object obj = hoveredPort.node.GetValue(hoveredPort);
-                    content.text += " = " + (obj != null ? obj.ToString() : "null");
-                }
+            if (hoveredPort != null && NodeEditorPreferences.GetSettings().portTooltips && graphEditor != null) {
+                string tooltip = graphEditor.GetPortTooltip(hoveredPort);
+                if (string.IsNullOrEmpty(tooltip)) return;
+                GUIContent content = new GUIContent(tooltip);
                 Vector2 size = NodeEditorResources.styles.tooltip.CalcSize(content);
                 Rect rect = new Rect(Event.current.mousePosition - (size), size);
                 EditorGUI.LabelField(rect, content, NodeEditorResources.styles.tooltip);
diff --git a/Scripts/Editor/NodeGraphEditor.cs b/Scripts/Editor/NodeGraphEditor.cs
index d33a3b3..ff2ca5c 100644
--- a/Scripts/Editor/NodeGraphEditor.cs
+++ b/Scripts/Editor/NodeGraphEditor.cs
@@ -70,6 +70,17 @@ namespace XNodeEditor {
             return NodeEditorPreferences.GetTypeColor(type);
         }
 
+        public virtual string GetPortTooltip(XNode.NodePort port) {
+            Type portType = port.ValueType;
+            string tooltip = "";
+            tooltip = portType.PrettyName();
+            if (port.IsOutput) {
+                object obj = port.node.GetValue(port);
+                tooltip += " = " + (obj != null ? obj.ToString() : "null");
+            }
+            return tooltip;
+        }
+
         /// <summary> Deal with objects dropped into the graph through DragAndDrop </summary>
         public virtual void OnDropObjects(UnityEngine.Object[] objects) {
             Debug.Log("No OnDropItems override defined for " + GetType());