Added NullTargetCheck to WriteEditor class

Assets/Fungus/UI/Editor/WriteEditor.cs

@@ -34,6 +34,9 @@ namespace Fungus
 
 		protected virtual void OnEnable()
 		{
+			if (NullTargetCheck()) // Check for an orphaned editor instance
+				return;
+
 			textObjectProp = serializedObject.FindProperty("textObject");
 			textProp = serializedObject.FindProperty("text");
 			descriptionProp = serializedObject.FindProperty("description");