diff --git a/frontend-js/src/main/js/map/CustomMap.js b/frontend-js/src/main/js/map/CustomMap.js
index 6c9b0d4a2791212e038e00bf8eba226db2f5fecb..a496b3a4f2ff4d62da4066f835f3f3e569a13d29 100644
--- a/frontend-js/src/main/js/map/CustomMap.js
+++ b/frontend-js/src/main/js/map/CustomMap.js
@@ -460,17 +460,16 @@ CustomMap.prototype.registerSource = function(overlayCollection) {
 
 CustomMap.prototype.refreshComments = function() {
   var self = this;
-  for ( var overlayName in this.overlayCollections) {
-    if (this.overlayCollections.hasOwnProperty(overlayName) && overlayName === "comment") {
-      var collection = this.overlayCollections[overlayName];
-      self.clearOverlayCollection(collection);
-      if (ServerConnector.getSessionData(self.getProject()).getShowComments()) {
-        return collection.refresh().then(function(){
-          return self.renderOverlayCollection({overlayCollection:collection});        
-        });
-      } else {
-        return collection.clear();
-      }
+  
+  var collection = self.getOverlayByName("comment");
+  if (collection!==undefined) {
+    self.clearOverlayCollection(collection);
+    if (ServerConnector.getSessionData(self.getProject()).getShowComments()) {
+      return collection.refresh().then(function(){
+        return self.renderOverlayCollection({overlayCollection:collection});        
+      });
+    } else {
+      return collection.clear();
     }
   }
   throw new Error("comment OverlayCollection not found");