Shadow not showing google maps marker

Shadow not showing google maps marker

Having a problem, I'm trying to add a custom shadow but somehow it is not
showing. I checked for bugs using firebug but nothing wrong, the path is
also correct. I have no idea why it's not working. code below.
var marker = new google.maps.Marker({
map: map,
position: latlngset,
shadow: 'codes/icon/shadow.png',
icon: baseicon+icon
});