updateTabIndex (index) {
      if (this.focusableItems.length > 0) {
        const nodeAtIndex = this.focusableItems[index]
        this.focusableItems.forEach((node) => {
          if (node !== nodeAtIndex) {
            node.setAttribute('tabindex', -1)
          }
        })
        nodeAtIndex.setAttribute('tabindex', 0)
      }
    }
Updates tab index for menulist items
@param {Number} index Position index of menu list item