diff --git a/inginious/frontend/pages/taskset_admin/task_edit.py b/inginious/frontend/pages/taskset_admin/task_edit.py
index cf4631a5c..cca6a21c3 100644
--- a/inginious/frontend/pages/taskset_admin/task_edit.py
+++ b/inginious/frontend/pages/taskset_admin/task_edit.py
@@ -46,6 +46,8 @@ def GET_AUTH(self, tasksetid, taskid):  # pylint: disable=arguments-differ
         environment_types = self.environment_types
         environments = self.environments
 
+        problemdata = [(id, dict(item)) for id, item in list(task_data.get('problems', {}).items())] # odict to tuple list
+
         current_filetype = None
         try:
             current_filetype = self.task_factory.get_task_descriptor_extension(taskset.get_id(), taskid)
@@ -59,7 +61,7 @@ def GET_AUTH(self, tasksetid, taskid):  # pylint: disable=arguments-differ
         return self.template_helper.render("taskset_admin/task_edit.html", taskset=taskset, taskid=taskid,
                                            problem_types=self.task_factory.get_problem_types(), task_data=task_data,
                                            environment_types=environment_types, environments=environments,
-                                           problemdata=json.dumps(task_data.get('problems', {})),
+                                           problemdata=problemdata,
                                            contains_is_html=self.contains_is_html(task_data),
                                            current_filetype=current_filetype,
                                            available_filetypes=available_filetypes,
diff --git a/inginious/frontend/static/js/studio.js b/inginious/frontend/static/js/studio.js
index c2c7acc80..033d0f51e 100644
--- a/inginious/frontend/static/js/studio.js
+++ b/inginious/frontend/static/js/studio.js
@@ -22,9 +22,8 @@ function refresh_codemirror()
  * Load the studio, creating blocks for existing subproblems
  */
 function studio_load(data)
-{
-    jQuery.each(data, function(pid, problem)
-    {
+{   
+    data.forEach(([pid, problem]) => {
         var template = "#subproblem_" + problem["type"];
         studio_create_from_template(template, pid);
         studio_init_template(pid, problem);
@@ -334,7 +333,7 @@ function studio_create_new_subproblem()
     var new_subproblem_type = $('#new_subproblem_type').val();
     if(!new_subproblem_pid.match(/^[a-zA-Z0-9_\-]+$/))
     {
-        alert('Problem id should only contain alphanumeric characters (in addition to "_" and "-").');
+        alert('Invalid problem id. It should only contain alphanumeric characters (in addition to "_" and "-") and shouldn\'t be empty.');
         return;
     }
 
diff --git a/inginious/frontend/templates/taskset_admin/task_edit.html b/inginious/frontend/templates/taskset_admin/task_edit.html
index b556971b5..4fa7a83e6 100644
--- a/inginious/frontend/templates/taskset_admin/task_edit.html
+++ b/inginious/frontend/templates/taskset_admin/task_edit.html
@@ -140,8 +140,7 @@ <h2>
 <!-- Init the javascript for the subproblem tab -->
 <script type="text/javascript">
     delete_subproblem_message = '{{_("Are you sure that you want to delete this subproblem?")}}';
-    problem_data = {{ problemdata | tojson }};
-    $(function(){ studio_load(JSON.parse(problem_data)); });
+    $(function(){ studio_load({{ problemdata | tojson }}); });
 </script>
 
 {% endblock %}