I was just wondering if it was possible to update the value of a key in the Mage::registry
without unsetting and resetting the item in the registry.
e.g.
$ids = array('1', '2', '3');
Mage::register('testing-key', $ids);
$re_ids = Mage::registry('testing-key');
$re_ids[] = '4';
Mage::registry('testing-key') = $re_ids;