Scroll bar in drop-down list

I have a drop down list with numerous choices. So many that a scroll bar is needed. The scroll bar shows on the form but it does not work. My users must use the arrow keys to scroll.

You may see this at the bottom of this webpage..... http://www.jaxareagolf.org/index.php/meeting-notice%E2%80%8E

Thanks for any help.

Barney