render(): void {
    super.render()

    if (!this.model.is_split_button) {
      this.el.classList.add("bk-bs-dropdown")
      this.buttonEl.classList.add("bk-bs-dropdown-toggle")
      this.buttonEl.appendChild(span({class: "bk-bs-caret"}))
    } else {
      this.el.classList.add("bk-bs-btn-group")
      const caretEl = this._render_button(span({class: "bk-bs-caret"}))
      caretEl.classList.add("bk-bs-dropdown-toggle")
      caretEl.addEventListener("click", (event) => this._caret_click(event))
      this.el.appendChild(caretEl)
    }

    if (this.model.active)
      this.el.classList.add("bk-bs-open")

    const items = []
    for (const item of this.model.menu) {
      let itemEl: HTMLElement
      if (item != null) {
        const [label, value] = item
        const link = a({}, label)
        link.dataset.value = value
        link.addEventListener("click", (event) => this._item_click(event))
        itemEl = li({}, link)
      } else
        itemEl = li({class: "bk-bs-divider"})
      items.push(itemEl)
    }

    const menuEl = ul({class: "bk-bs-dropdown-menu"}, items)
    this.el.appendChild(menuEl)
  }

  protected _render_items(completions: string[]): void {
    empty(this.menuEl)

    for (const text of completions) {
      const itemEl = li({}, a({data: {text: text}}, text))
      this.menuEl.appendChild(itemEl)
    }
  }

 const tabs = this.model.tabs.map((tab, i) => li({}, span({data: {index: i}}, tab.title)))