public void deregisterSettingChangeListener(String key,SettingChangeListener listener){
  List<SettingChangeListener> list=listeners.get("config. " + key);
  if (list != null) {
    list.remove(listener);
  }
}

public void deregisterSettingChangeListener ( String key , SettingChangeListener listener ) { List < SettingChangeListener > list = listeners . get ( "config. " + key ) ; if ( list != null ) { list . remove ( listener ) ; } }
deregister a change listener .
