diff --git a/mindplot/src/main/javascript/Designer.js b/mindplot/src/main/javascript/Designer.js
index 6ae482a1..8613ae9f 100644
--- a/mindplot/src/main/javascript/Designer.js
+++ b/mindplot/src/main/javascript/Designer.js
@@ -697,7 +697,7 @@ 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) {
+            $assert(targetTopic, "targetTopic could not be found:" + targetTopicId + dmodel.getTopics().map(function (e) {
                 return e.getId()
             }));