diff --git a/Scripts/Editor/NodeEditorGUI.cs b/Scripts/Editor/NodeEditorGUI.cs
old mode 100644
new mode 100755
index 74530d8..358b2e5
--- a/Scripts/Editor/NodeEditorGUI.cs
+++ b/Scripts/Editor/NodeEditorGUI.cs
@@ -17,7 +17,7 @@ namespace XNodeEditor {
         public event Action onLateGUI;
         private static readonly Vector3[] polyLineTempArray = new Vector3[2];
 
-        private void OnGUI() {
+        protected virtual void OnGUI() {
             Event e = Event.current;
             Matrix4x4 m = GUI.matrix;
             if (graph == null) return;