// Get markup associated with Border or Panel component
final MarkupStream originalMarkupStream = getMarkupStream();
final MarkupStream associatedMarkupStream = getAssociatedMarkupStream(true);
// skip until the targetted tag is found
associatedMarkupStream.skipUntil(openTagName);
setMarkupStream(associatedMarkupStream);
// Get open tag in associated markup of border component
final ComponentTag associatedMarkupOpenTag = associatedMarkupStream.getTag();