code: private void positionX(int secondX) {
  
          if (secondX < m_firstX) {
              setSelectPositionX(secondX, m_firstX - secondX);
          } else {
              setSelectWidth(secondX - m_firstX);
          }
      }
docs: Setting a new left/top value for the selection.<p>
  
  @param secondX the cursor X offset to the selection area