code: private int measureWidth(CmsContextMenuItemWidget item) {
  
          return item.getOffsetWidth()
              - CmsDomUtil.getCurrentStyleInt(item.getElement(), Style.paddingLeft)
              - CmsDomUtil.getCurrentStyleInt(item.getElement(), Style.paddingRight);
      }
docs: Measures the width of a context menu item.<p>
  
  @param item the menu item
  @return the width