code: public void openNextTo(CmsContextMenuItemWidget parentMenuItem) {
  
          int left = parentMenuItem.getAbsoluteLeft() + parentMenuItem.getOffsetWidth();
          int top = parentMenuItem.getAbsoluteTop() - Window.getScrollTop();
  
          showAt(left, top);
      }
docs: Opens next to the given parent item.<p>
  
  @param parentMenuItem the perent item