beforeShow event not firing on jQueryUI Datepicker

Question

No matter what I try, I'm not able to get the beforeShow event to fire on my datepicker. Here's my code:

$('#calendar').datepicker({
inline: true,
dateFormat: 'mm,dd,yy',
beforeShow: function(input, inst) { alert('before'); }
});

I've added beforeShowDay and onSelect events to my datepicker, and they do fire correctly. Has anyone else had trouble with this?