/** Returns the default user interface single value property descriptors.
	* These are the names of all 
	* sinlge value propertyDesctiptors except label, id or *Id
	* but if that would be empty, label
	* @return Array of PntPropertyDescriptor
	*/
	function getUiPropertyDescriptors() 
	{
		$result = array();
		$props = $this->getSingleValuePropertyDescriptors();
        foreach ($props as $name => $prop) {
			if ($prop->getVisible())
				$result[$name] = $prop;
		}
		return $result;
	}