docs: @Override
      public ObservableList<PropertySheet.Item> getPropertySheetItems() {
          ObservableList<PropertySheet.Item> items = super.getPropertySheetItems();
  
          items.add(new PropertySheet.Item() {
  
              @Override
              public Optional<ObservableValue<?>> getObservableValue() {
                  return Optional.of(displayModeProperty());
              }
  
              @Override
              public void setValue(Object value) {
                  setDisplayMode((DisplayMode) value);
              }
  
              @Override
              public Object getValue() {
                  return getDisplayMode();
              }
  
              @Override
              public Class<?> getType() {
                  return DisplayMode.class;
              }
  
              @Override
              public String getName() {
                  return "Display Mode"; //$NON-NLS-1$
              }
  
              @Override
              public String getDescription() {
                  return "Grid or Column Layout"; //$NON-NLS-1$
              }
  
              @Override
              public String getCategory() {
                  return YEAR_PAGE_CATEGORY;
              }
          });
  
          return items;
      }