Description:
------------
Extending some DOM classes (f.e. DOMDOcument, DOMElement I think others, but not 
tested) work. But when such elemenmt appended to the document, additional 
information lost. Meantime, when copy of object saved alsewere, all work as 
expected.

First mention of this bug and initial workaround in comment 
http://php.net/manual/tr/book.dom.php#80613 by ryoroxdahouse at hotmail dot com.

I make automattical workaround like ( 
http://hinikato.blogspot.com/2009/10/domelement.html?
showComment=1270202266600#c284093039037001302 ):
class MyElement extends DOMElement
{
public function __construct($name, $value = null, $uri = null) {
parent::__construct($name, $value, $uri);
$GLOBALS['PHP_HACK_DOM_ELEMENT'][spl_object_hash($this)] = $this; //Note, 
reference is not enough :(
}

public function __destruct() {
unset($GLOBALS['PHP_HACK_DOM_ELEMENT'][spl_object_hash($this)]);
}
}

But as we need object copy, not just reference it requires double of memmory!

Test script:
---------------
<?
class MyElement extends DOMElement{}
$doc = new DOMDocument();
$doc->appendChild(new MyElement('test'));
var_dump($doc->documentElement);
?>

Expected result:
----------------
object(MyElement)#4 (0) { } 

Actual result:
--------------
object(DOMElement)#4 (0) { }