code: function() {
        if (!this.openAsModal_) { return; }
        this.openAsModal_ = false;
        this.dialog_.style.zIndex = '';
  
        // This won't match the native <dialog> exactly because if the user set top on a centered
        // polyfill dialog, that top gets thrown away when the dialog is closed. Not sure it's
        // possible to polyfill this perfectly.
        if (this.replacedStyleTop_) {
          this.dialog_.style.top = '';
          this.replacedStyleTop_ = false;
        }
  
        // Clear the backdrop and remove from the manager.
        this.backdrop_.parentNode && this.backdrop_.parentNode.removeChild(this.backdrop_);
        dialogPolyfill.dm.removeDialog(this);
      }
docs: Remove this dialog from the modal top layer, leaving it as a non-modal.