diff --git a/Scripts/Editor/NodeEditorGUI.cs b/Scripts/Editor/NodeEditorGUI.cs
index e3f8c4c..87b2775 100644
--- a/Scripts/Editor/NodeEditorGUI.cs
+++ b/Scripts/Editor/NodeEditorGUI.cs
@@ -213,7 +213,7 @@ namespace XNodeEditor {
                 hoveredPort = null;
             }
 
-            List<UnityEngine.Object> preSelection = new List<UnityEngine.Object>(preBoxSelection);
+            List<UnityEngine.Object> preSelection = preBoxSelection != null ? new List<UnityEngine.Object>(preBoxSelection) : new List<UnityEngine.Object>();
 
             //Save guiColor so we can revert it
             Color guiColor = GUI.color;