code: public synchronized SXTag addChildNode(String tagName) throws IOException {
  		// reject modification of already closed node
  		if(isOpen==false) {
  			throw new IOException("Attempted to add child node '" + tagName + "' to already closed tag '" + name + "'!");
  		}
  		if(lastChildNode==null) {
  			// no child nodes yet, close opening tag
  			writer.write(">");
  		} else {
  			lastChildNode.close();
  		}
  		// regular child tags start in new line
  		writer.write("\n");
  		// create, register and return new child node
  		SXTag childNode = new SXTag(tagName, writer, tabLevel+1, tabString);
  		lastChildNode = childNode;
  		return childNode;
  	}
docs: Adds a regular tag child node with the specified tag name to this node.
  <b>WARNING:</b> This will close the last added child node, if applicable!
  <b>NOTICE:</b> Use this method to add child nodes, do <b>NOT</b> attempt to instantiate them manually!
  
  @param tagName Name of the tag node to be added
  @return The newly created tag