false.
      this.__shouldRemoveTabIndex = false;
      // Used for wrapping the focus on TAB / Shift+TAB.
      this.__firstFocusableNode = this.__lastFocusableNode = null;
      // Used by __onNextAnimationFrame to cancel any previous callback.
      this.__raf = null;
      // Focused node before overlay gets opened. Can be restored on close.
      this.__restoreFocusNode = null;
      this._ensureSetup();
    },

    attached: function() {
      // Call _openedChanged here so that position can be comput