willDestroy() {
    const listHeader = this.el.querySelector('.list-header');
    if (listHeader) {
      listHeader.removeEventListener('contextmenu', this.showBasicContext);
    }
    this.layoutService.off('content-height-update', this.onResize);
    return super.willDestroy(...arguments);
  }
Hook called when the component element will be destroyed.
Clean up everything.

@method willDestroy