@Override
  public void readExternal(final Element element) throws InvalidDataException {
    final String value = element.getAttributeValue(VALUE_ATTRIBUTE);
    myUrl = value != null ? value : "";
    final String protocol = VirtualFileManager.extractProtocol(myUrl);
    if (protocol == null) myUrl = urlValue(myUrl);
  }
@Override
  public void readExternal(final Element element)