public function WPCB_wp_get_revision_ui_diff($diff, $compare_from, $compare_to)
 {
     if (get_post($compare_from->post_parent)->post_type != "itemmc") {
         return $diff;
     }
     $eal_From = new EAL_ItemMC();
     $eal_From->loadById($compare_from->ID);
     $eal_To = new EAL_ItemMC();
     $eal_To->loadById($compare_to->ID);
     $diff[0] = $eal_From->compareTitle($eal_To);
     $diff[1] = $eal_From->compareDescription($eal_To);
     $diff[2] = $eal_From->compareQuestion($eal_To);
     $diff[3] = $eal_From->compareLevel($eal_To);
     $diff[4] = $eal_From->compareAnswers($eal_To);
     return $diff;
 }