public function is_feedback_modified(stdClass $grade, stdClass $data) {
        // We only need to know if the source user's PDF has changed. If so then all
        // following users will have the same status. If it's only an individual annotation
        // then only one user will come through this method.
        // Source user id is only added to the form if there was a pdf.
        if (!empty($data->editpdf_source_userid)) {
            $sourceuserid = $data->editpdf_source_userid;
            // Retrieve the grade information for the source user.
            $sourcegrade = $this->assignment->get_user_grade($sourceuserid, true, $grade->attemptnumber);
            $pagenumbercount = document_services::page_number_for_attempt($this->assignment, $sourceuserid, $sourcegrade->attemptnumber);
            for ($i = 0; $i < $pagenumbercount; $i++) {
                // Select all annotations.
                $draftannotations = page_editor::get_annotations($sourcegrade->id, $i, true);
                $nondraftannotations = page_editor::get_annotations($grade->id, $i, false);
                // Check to see if the count is the same.
                if (count($draftannotations) != count($nondraftannotations)) {
                    // The count is different so we have a modification.
                    return true;
                } else {
                    $matches = 0;
                    // Have a closer look and see if the draft files match all the non draft files.
                    foreach ($nondraftannotations as $ndannotation) {
                        foreach ($draftannotations as $dannotation) {
                            foreach ($ndannotation as $key => $value) {
                                if ($key != 'id' && $value != $dannotation->{$key}) {
                                    continue 2;
                                }
                            }
                            $matches++;
                        }
                    }
                    if ($matches !== count($nondraftannotations)) {
                        return true;
                    }
                }
                // Select all comments.
                $draftcomments = page_editor::get_comments($sourcegrade->id, $i, true);
                $nondraftcomments = page_editor::get_comments($grade->id, $i, false);
                if (count($draftcomments) != count($nondraftcomments)) {
                    return true;
                } else {
                    // Go for a closer inspection.
                    $matches = 0;
                    foreach ($nondraftcomments as $ndcomment) {
                        foreach ($draftcomments as $dcomment) {
                            foreach ($ndcomment as $key => $value) {
                                if ($key != 'id' && $value != $dcomment->{$key}) {
                                    continue 2;
                                }
                            }
                            $matches++;
                        }
                    }
                    if ($matches !== count($nondraftcomments)) {
                        return true;
                    }
                }
            }
        }
        return false;
    }