code: protected void moveAllLeftToRight() {
          int sz = dataModel.getSize();
          int[] selected = new int[sz];
          for (int i = 0; i < sz; i++) {
              selected[i] = i;
          }
          helperList.setSelectedIndices(selected);
          update();
      }
docs: Move all the source items to the chosen side. I.e., select all the items.