private static function _loadFromBuild()
 {
     if (!isset(self::$_supportedContexts)) {
         if (file_exists('build/component/masterlayoutcontexts')) {
             $data = unserialize(file_get_contents('build/component/masterlayoutcontexts'));
             self::$_supportedContexts = $data['contexts'];
             self::$_supportedBoxContexts = $data['boxContexts'];
         } else {
             self::$_supportedContexts = array();
             self::$_supportedBoxContexts = array();
         }
     }
 }