docs: public void endElement() throws KNXMLException
  	{
  		if (layout.empty())
  			throw new KNXIllegalStateException("no elements to end");
  		try {
  			((Tag) layout.pop()).endTag();
  			if (layout.empty())
  				w.flush();
  		}
  		catch (final IOException e) {
  			throw new KNXMLException(e.getMessage());
  		}
  	}