code: @Override
      public void onBrowserEvent(Event event) {
  
          super.onBrowserEvent(event);
  
          switch (DOM.eventGetType(event)) {
              case Event.ONMOUSEUP:
                  Event.releaseCapture(m_slider.getElement());
                  m_capturedMouse = false;
                  break;
              case Event.ONMOUSEDOWN:
                  Event.setCapture(m_slider.getElement());
                  m_capturedMouse = true;
                  //$FALL-THROUGH$
              case Event.ONMOUSEMOVE:
                  if (m_capturedMouse) {
                      event.preventDefault();
                      float x = ((event.getClientX() - (m_colorUnderlay.getAbsoluteLeft())) + Window.getScrollLeft());
                      float y = ((event.getClientY() - (m_colorUnderlay.getAbsoluteTop())) + Window.getScrollTop());
  
                      if (m_parent != null) {
                          m_parent.onMapSelected(x, y);
                      }
  
                      setSliderPosition(x, y);
                  }
                  //$FALL-THROUGH$
              default:
  
          }
      }
docs: Fired whenever a browser event is received.
  @param event Event to process