docs: public void setFirstLast(boolean first, boolean last, boolean hideAdd) {
  
          CmsEditableGroupButtonsState state = (CmsEditableGroupButtonsState)getState(false);
          if ((state.isFirst() != first) || (state.isLast() != last)) {
              state.setFirst(first);
              state.setLast(last);
              state.setAddOptionHidden(hideAdd);
              markAsDirty();
          }
      }