Datepicker adds blank space on the bottom of a page on IE 7

Datepicker adds blank space on the bottom of a page on IE 7

Hi guys:

I am facing a problem with the datepicker, the thing is the first time the page loads there is an empty space after the footer of the page (I have Header - Body - Footer Layout), but as soon as I click on the Picker the empty space goes away and the page looks as normal.  I am using html 4 as doctype.

Thanks in advance.