@Override
  @NotNull
  public Collection<StructureViewTreeElement> getChildrenBase() {
    final XmlTag tag = getElement();
    if (tag == null || !tag.isValid()) return Collections.emptyList();
    return ContainerUtil.map(tag.getSubTags(), HtmlTagTreeElement::new);
  }
@Override
  @NotNull
  public Collection<StructureViewTreeElement> getChildrenBase()