diff --git a/grade/grading/form/lib.php b/grade/grading/form/lib.php
index 8e1ebe904cb99..d66ae077c4e0e 100644
--- a/grade/grading/form/lib.php
+++ b/grade/grading/form/lib.php
@@ -368,10 +368,10 @@ protected function get_instance($instance) {
      * @param int $itemid
      * @return gradingform_instance
      */
-    public function create_instance($raterid, $itemid) {
+    public function create_instance($raterid, $itemid = null) {
         global $DB;
         // first find if there is already an active instance for this itemid
-        if ($current = $this->get_current_instance($raterid, $itemid)) {
+        if ($itemid && $current = $this->get_current_instance($raterid, $itemid)) {
             return $this->get_instance($current->copy($raterid, $itemid));
         } else {
             $class = 'gradingform_'. $this->get_method_name(). '_instance';
@@ -588,6 +588,9 @@ protected function make_active() {
             // already active
             return;
         }
+        if (empty($this->data->itemid)) {
+            throw new coding_exception('You cannot mark active the grading instance without itemid');
+        }
         $currentid = $this->get_controller()->get_current_instance($this->data->raterid, $this->data->itemid, true);
         if ($currentid) {
             if ($currentid != $this->get_id()) {
@@ -618,9 +621,22 @@ public function cancel() {
      * Updates the instance with the data received from grading form. This function may be
      * called via AJAX when grading is not yet completed, so it does not change the
      * status of the instance.
+     *
+     * @param array $elementvalue
      */
     public function update($elementvalue) {
-        // TODO update timemodified at least
+        global $DB;
+        $newdata = new stdClass();
+        $newdata->id = $this->get_id();
+        $newdata->timemodified = time();
+        if (isset($elementvalue['itemid']) && $elementvalue['itemid'] != $this->data->itemid) {
+            $newdata->itemid = $elementvalue['itemid'];
+        }
+        // TODO also update: rawgrade, feedback, feedbackformat
+        $DB->update_record('grading_instances', $newdata);
+        foreach ($newdata as $key => $value) {
+            $this->data->$key = $value;
+        }
     }
 
     /**
@@ -632,10 +648,16 @@ abstract public function get_grade();
 
     /**
      * Called when teacher submits the grading form:
-     * updates the instance in DB, marks it as ACTIVE and returns the grade to be pushed to the gradebook
+     * updates the instance in DB, marks it as ACTIVE and returns the grade to be pushed to the gradebook.
+     * $itemid must be specified here (it was not required when the instance was
+     * created, because it might not existed in draft)
+     *
+     * @param array $elementvalue
+     * @param int $itemid
      * @return int the grade on 0-100 scale
      */
-    public function submit_and_get_grade($elementvalue) {
+    public function submit_and_get_grade($elementvalue, $itemid) {
+        $elementvalue['itemid'] = $itemid;
         $this->update($elementvalue);
         $this->make_active();
         return $this->get_grade();
diff --git a/grade/grading/form/rubric/lib.php b/grade/grading/form/rubric/lib.php
index f788b8bfdac1c..0be5fa62b1405 100644
--- a/grade/grading/form/rubric/lib.php
+++ b/grade/grading/form/rubric/lib.php
@@ -457,11 +457,13 @@ public function get_rubric_filling($force = false) {
      * Updates the instance with the data received from grading form. This function may be
      * called via AJAX when grading is not yet completed, so it does not change the
      * status of the instance.
+     *
+     * @param array $data
      */
     public function update($data) {
         global $DB;
         $currentgrade = $this->get_rubric_filling();
-        parent::update($data); // TODO ? +timemodified
+        parent::update($data);
         foreach ($data['criteria'] as $criterionid => $record) {
             if (!array_key_exists($criterionid, $currentgrade['criteria'])) {
                 $newrecord = array('forminstanceid' => $this->get_id(), 'criterionid' => $criterionid,
diff --git a/mod/assignment/lib.php b/mod/assignment/lib.php
index 0a30eb4464f87..ec602d8f502ce 100644
--- a/mod/assignment/lib.php
+++ b/mod/assignment/lib.php
@@ -1067,11 +1067,11 @@ function display_submission($offset=-1,$userid =-1, $display=true) {
             $mformdata->fileui_options = array('subdirs'=>0, 'maxbytes'=>$CFG->userquota, 'maxfiles'=>1, 'accepted_types'=>'*', 'return_types'=>FILE_INTERNAL);
         }
         if ($controller = get_grading_manager($this->context, 'mod_assignment', 'submission')->get_active_controller()) {
-            if (!isset($submission->id)) {
-                // we create a submission if it does not exist yet because we need submission->id for grading
-                $mformdata->submission = $this->get_submission($user->id, true);
+            $itemid = null;
+            if (!empty($submission->id)) {
+                $itemid = $submission->id;
             }
-            $mformdata->advancedgradinginstance = $controller->create_instance($USER->id, $mformdata->submission->id);
+            $mformdata->advancedgradinginstance = $controller->create_instance($USER->id, $itemid);
         }
 
         $submitform = new mod_assignment_grading_form( null, $mformdata );
@@ -1613,7 +1613,9 @@ function validate_and_preprocess_feedback() {
             // preprocess advanced grading here
             if ($gradinginstance) {
                 $data = $mform->get_data();
-                $_POST['xgrade'] = $gradinginstance->submit_and_get_grade($data->advancedgrading);
+                // create submission if it did not exist yet because we need submission->id for storing the grading instance
+                $submission = $this->get_submission($userid, true);
+                $_POST['xgrade'] = $gradinginstance->submit_and_get_grade($data->advancedgrading, $submission->id);
             }
         }
         return true;