diff --git a/main/exercice/exercise_submit.php b/main/exercice/exercise_submit.php
index a0c788568a..3b1eabc577 100755
--- a/main/exercice/exercise_submit.php
+++ b/main/exercice/exercise_submit.php
@@ -26,7 +26,7 @@
 *   Modified by hubert.borderiou (2011-10-21 question category)
 */
 
-use \ChamiloSession as Session;
+use ChamiloSession as Session;
 
 require_once '../inc/global.inc.php';
 $current_course_tool  = TOOL_QUIZ;
@@ -236,7 +236,6 @@ $exercise_stat_info = $objExercise->get_stat_track_exercise_info(
 
 $clock_expired_time = null;
 
-
 if (empty($exercise_stat_info)) {
     if ($debug)  error_log('5  $exercise_stat_info is empty ');
 	$total_weight = 0;
@@ -833,7 +832,12 @@ if (!empty($error)) {
 
     echo '<script>
         $(function() {
-            //$(".exercise_save_now_button").hide();
+
+            // Block form submition on enter
+            $(".block_on_enter").keypress(function(event) {
+                return event.keyCode != 13;
+            });
+
             $(".main_question").mouseover(function() {
                 //$(this).find(".exercise_save_now_button").show();
                 //$(this).addClass("question_highlight");