private void showFeedbackArea(Map<String, Object> state) {
    @SuppressWarnings("unchecked")
    List<String> feedbackHistory = (List<String>)state.get(FEEDBACKHISTORY);
    this.feedbackArea.clear();
    if (feedbackHistory != null){
      this.feedbackArea.add(this.createFeedbackPanel(feedbackHistory));
    }
  }