diff --git a/app/assets/javascripts/editor/editor.js.erb b/app/assets/javascripts/editor/editor.js.erb
index 3a41285b..bfcf6ac9 100644
--- a/app/assets/javascripts/editor/editor.js.erb
+++ b/app/assets/javascripts/editor/editor.js.erb
@@ -436,14 +436,21 @@ configureEditors: function () {
     if (result.error_messages) {
         const targetNode = card.find('.row .col-sm-9').eq(3);
 
+        let errorMessagesToShow = [];
+        result.error_messages.forEach(function (item) {
+            if (item) {
+              errorMessagesToShow.push(item)
+            }
+        })
+
         // one or more errors?
-        if (result.error_messages.length > 1) {
+        if (errorMessagesToShow.length > 1) {
             // delete all current elements
             targetNode.text('');
             // create a new list and appand each element
             const ul = document.createElement("ul");
             ul.setAttribute('class', 'error_messages_list');
-            result.error_messages.forEach(function (item) {
+            errorMessagesToShow.forEach(function (item) {
                 var li = document.createElement("li");
                 var text = document.createTextNode(item);
                 li.appendChild(text);
@@ -451,7 +458,7 @@ configureEditors: function () {
             })
             targetNode.append(ul);
         } else {
-            targetNode.text(result.error_messages.join(''));
+            targetNode.text(errorMessagesToShow.join(''));
         }
     }
     //card.find('.row .col-sm-9').eq(4).find('a').attr('href', '#output-' + index);