When I want to set reference to $this object gets copied.
In this example $ui_handler contains copy of object $test.
$ui_handler -> data is not reference to $test,

<?
class CUI_element {
	var $value;
	function CUI_element($value) {
		global $ui_handler;
		$this -> value = $value;
		$ui_handler -> register($this);		
	}
}

class CUI_handler {
	var $data;
	
	function CUI_handler() {
		$this -> data = false;
	}
	
	function register(&$element) {
		$this -> data = &$element;
	}
};

$ui_handler = new CUI_Handler();
$test = new CUI_Element("test");
$test -> value = "changed";
var_dump($ui_handler -> data); print "<br>";
var_dump($test); print "<br>";
?>

My output:
object(cui_element)(1) { ["value"]=> string(4) "test" } 
object(cui_element)(1) { ["value"]=> string(7) "changed" } 

Working url: http://biuro.pablosoft.com.pl/~zork/ref/tests.php

regards
Zork.