diff --git a/mindplot/src/main/javascript/Designer.js b/mindplot/src/main/javascript/Designer.js
index 8b9cbb76..6ae482a1 100644
--- a/mindplot/src/main/javascript/Designer.js
+++ b/mindplot/src/main/javascript/Designer.js
@@ -697,6 +697,9 @@ mindplot.Designer = new Class({
 
             var targetTopicId = model.getToNode();
             var targetTopic = dmodel.findTopicById(targetTopicId);
+            $assert(targetTopic, "targetTopic could not be found:" + targetTopicId + dmodel.getTopics().forEach(function (e) {
+                return e.getId()
+            }));
 
             // Build relationship line ....
             var result = new mindplot.Relationship(sourceTopic, targetTopic, model);
diff --git a/mindplot/src/main/javascript/model/RelationshipModel.js b/mindplot/src/main/javascript/model/RelationshipModel.js
index 55f909e7..8bd0885e 100644
--- a/mindplot/src/main/javascript/model/RelationshipModel.js
+++ b/mindplot/src/main/javascript/model/RelationshipModel.js
@@ -93,7 +93,7 @@ mindplot.model.RelationshipModel = new Class({
         this._startArrow = startArrow;
     },
 
-    clone:function (model) {
+    clone:function () {
         var result = new mindplot.model.RelationshipModel(this._sourceTargetId, this._targetTopicId);
         result._id = this._id;
         result._lineType = this._lineType;