code: private void setToolTipPosition(int clientLeft, int clientTop) {
  
          if (m_toolTip != null) {
              int height = m_toolTip.getOffsetHeight();
              int width = m_toolTip.getOffsetWidth();
              int windowHeight = Window.getClientHeight();
              int windowWidth = Window.getClientWidth();
              int scrollLeft = Window.getScrollLeft();
              int scrollTop = Window.getScrollTop();
              int left = clientLeft + scrollLeft + m_offsetLeft;
              if ((left + width) > (windowWidth + scrollLeft)) {
                  left = (windowWidth + scrollLeft) - m_offsetLeft - width;
              }
              m_toolTip.getStyle().setLeft(left, Unit.PX);
              int top = clientTop + scrollTop + m_offsetTop;
              if (((top + height) > (windowHeight + scrollTop)) && ((height + m_offsetTop) < clientTop)) {
                  top = (clientTop + scrollTop) - m_offsetTop - height;
              }
              m_toolTip.getStyle().setTop(top, Unit.PX);
          }
      }
docs: Sets the tool-tip position.<p>
  
  @param clientLeft the mouse pointer left position relative to the client window
  @param clientTop the mouse pointer top  position relative to the client window