/**
  * Staticly build template placeholders array
  * @return void
  */
 public static final function makePlaceholders()
 {
     if (is_array(self::$placeholders)) {
         return;
     }
     // Static initialisations
     self::$placeholders = array();
     foreach (CAppUI::conf("template_placeholders") as $_class => $_active) {
         if ($_active) {
             if (!class_exists($_class)) {
                 trigger_error("Template placeholder missing class '{$_class}'", E_USER_ERROR);
                 continue;
             }
             self::$placeholders[$_class] = new $_class();
         }
     }
 }