When I want to set reference to $this obiect gets copied.

<?
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);
?>