code: function reveal(error, focus) {
          if (error instanceof filterTree.Error && error.node && (focus === undefined || focus)) {
              var el = error.node.el;
              while (el && !(el.tagName === 'SECTION' && el.parentElement.classList.contains('tabz'))) {
                  el = el.parentElement;
              }
              if (el) {
                  tabz.tabTo(el);
              }
          }
          return error;
      }
docs: If a FilterTreeError with a node property and we're focused, search up the DOM to the nearest folder and reveal it.
  > _Folder_ is defined as a `<section>` tag inside an element of `tabz` class.
  @param {FilterTreeError} error
  @param {boolean} [focus=true]