code: private void maybeUpdateScrollbars() {
  
          if (!isAttached()) {
              return;
          }
  
          /*
           * Measure the height and width of the content directly. Note that measuring
           * the height and width of the container element (which should be the same)
           * doesn't work correctly in IE.
           */
          Widget w = getWidget();
          int contentHeight = (w == null) ? 0 : w.getOffsetHeight();
  
          // Determine which scrollbars to show.
          int realScrollbarHeight = 0;
          int realScrollbarWidth = 0;
          if ((m_scrollbar != null) && (getElement().getClientHeight() < contentHeight)) {
              // Vertical scrollbar is defined and required.
              realScrollbarWidth = m_verticalScrollbarWidth;
          }
  
          if (realScrollbarWidth > 0) {
              m_scrollLayer.getStyle().clearDisplay();
  
              m_scrollbar.setScrollHeight(Math.max(0, contentHeight - realScrollbarHeight));
          } else if (m_scrollLayer != null) {
              m_scrollLayer.getStyle().setDisplay(Display.NONE);
          }
          if (m_scrollbar instanceof I_CmsDescendantResizeHandler) {
              ((I_CmsDescendantResizeHandler)m_scrollbar).onResizeDescendant();
          }
          maybeUpdateScrollbarPositions();
      }
docs: Update the position of the scrollbars.<p>
  If only the vertical scrollbar is present, it takes up the entire height of
  the right side. If only the horizontal scrollbar is present, it takes up
  the entire width of the bottom. If both scrollbars are present, the
  vertical scrollbar extends from the top to just above the horizontal
  scrollbar, and the horizontal scrollbar extends from the left to just right
  of the vertical scrollbar, leaving a small square in the bottom right
  corner.<p>