code: private void positionY(int secondY) {
  
          if (secondY < m_firstY) {
              setSelectPositionY(secondY, m_firstY - secondY);
          } else {
              setSelectHeight(secondY - m_firstY);
          }
      }
docs: Setting a new top/height value for the selection.<p>
  
  @param secondY the cursor Y offset to the selection area