Datepicker, problem with background/clear

Datepicker, problem with background/clear

As you can see from the attached file, my datepicker looks kind of weird. If you look closely you can see that both #ui-datepicker-div and .ui-datepicker-header is "collapsed", and I figure some kind of clear is not working properly?

If I set the height manually to #ui-datepicker-div the whole background turns green (like I want it), but of course I need the height to be dynamic. All help is much appreciated!

Stian