Catch Everist, IE and Sub Menus

Hello, I'm experiencing a problem with Internet Explorer and Sub Menus with the Catch Everest 'free' theme. When the Parent menu item is hovered over, the height of the main menu (header-menu) div changes during this hover. It only happens in IE. http://www.eems.com.au:2010/wordpress/ However, the same site accessed via IP does not experience the problem. http://203.173.40.121:2010/wordpress/ If you can't recreate the problem, I have also included images of how it renders in my browser (IE 10) on the child page. http://203.173.40.121:2010/wordpress/index.php/parent/child/ Any help is appreciated.