Datepicker display Month and Year overlaps in IE 7

Datepicker display Month and Year overlaps in IE 7

Hi Guys:

When I set the month and year menus, it works fine with firefox but when I use IE 7 the year select comes undernet the month one, looking at the online demos it works fine in IE 7 as well, probably I am doing something wrong, by the way I am using html 4 as doctype.

Thanks in advance