Here is the solution to solve this problem.
(function($){
var datebox = $.fn.datebox.defaults.onChange;
$.fn.datebox.defaults.onChange = function(newValue, oldValue){
$(this).closest('form').trigger('change');
datebox.call(this, newValue, oldValue);
};
var combobox = $.fn.combobox.defaults.onChange;
$.fn.combobox.defaults.onChange = function(newValue, oldValue){
$(this).closest('form').trigger('change');
combobox.call(this, newValue, oldValue);
};
})(jQuery);
Please refer to the updated sample
http://jsfiddle.net/uAqKG/4/.