docs: function(syncAction){
      var oldAction = this.syncAction;
  
      if (typeof syncAction != 'function')
        syncAction = null;
  
      this.syncAction = syncAction;
  
      if (syncAction)
      {
        if (!oldAction)
          this.addHandler(this.syncEvents);
        if (this.isSyncRequired())
          callSyncAction(this);
      }
      else
      {
        if (oldAction)
          this.removeHandler(this.syncEvents);
      }
    }