element, element.classList.contains(CLASS_NAME_FADE))\n  }\n\n  _keydown(event) {\n    if (!([ARROW_LEFT_KEY, ARROW_RIGHT_KEY, ARROW_UP_KEY, ARROW_DOWN_KEY].includes(event.key))) {\n      return\n    }\n\n    event.stopPropagation()// stopPropagation/preventDefault both added to support up/down keys without scrolling the page\n    event.preventDefault()\n    const isNext = [ARROW_RIGHT_KEY, ARROW_DOWN_KEY].includes(event.key)\n    const nextActiveElement = getNextActiveElement(this._getChildren().filter(element...