public void arrowDown() {
    if (currentPosition < modes.size() - 1) {
      currentPosition += 1;
      showMode(currentPosition);
      showMode(currentPosition - 1);
      modeScreenView.refreshTerminal();
    }
  }
The presentation logic for the mode screen.
hbase-hbtop/src/main/java/org/apache/hadoop/hbase/hbtop/screen/mode/ModeScreenPresenter.java