code: @Override
      public Widget getWidget(int index) {
          if (index == PAGE_LIMIT - 1) {
              if (offPageContainer.isEmpty()) {
                  return offPageContainer.asWidget();
              }
              int deckIndex = offPageContainer.getSelectedDeck() == -1 ? 0 : offPageContainer.getSelectedDeck();
              return offPageContainer.getDeck(deckIndex);
          }
          return super.getWidget(index);
      }
docs: ------------------------------------------------------ properties