docs: protected void redraw() {
  
          if (isAttached()) {
              int outerHeight = getElement().getOffsetHeight();
              int innerHeight = m_containerElement.getOffsetHeight();
              if (outerHeight >= innerHeight) {
                  setScrollbarVisible(false);
              } else {
                  setScrollbarVisible(true);
                  adjustKnobHeight(outerHeight, innerHeight);
                  setKnobPosition(m_currentValue);
              }
          }
          if (m_slidingMouse) {
              m_mouseSlidingStartY = m_lastMouseY;
              m_mouseSlidingStartValue = m_currentValue;
          }
      }