@Override
    protected void onEnterKeyDown(final Context context,
                                  final Element parent,
                                  final R row,
                                  final NativeEvent event,
                                  final ValueUpdater<R> valueUpdater) {
        final Element element = event.getEventTarget().cast();
        if (ElementUtil.hasClassName(element, ACTION_MENU_CELL_CLASS_NAME, 5)) {
            final List<Item> items = NullSafe.get(menuCreator, mc -> mc.apply(row));
            if (NullSafe.hasItems(items)) {
                showActionMenu(row, event);
            }
        }
        if (valueUpdater != null) {
            valueUpdater.update(row);
        }
    }
@param menuCreator Function to create the menu items to display
stroom-core-client-widget/src/main/java/stroom/cell/info/client/ActionMenuCell.java