Select boxes with a mind of their own

[LimpBagel]

A small calendar popup for my site is behaving oddly. The select boxes for the hour, minutes, and AM/PM will sometimes take up the entire screen when you load the popup. It seems to happen randomly and never on a set pattern. Any idea what could cause this?

http://www.shortskates.com/calendar.JPG.

Should I post the code for those boxes?

[The Little Guy]

Before you post your code, validate your html http://validator.w3.org/ and if that still doesn't work, then post your code.