Since IE (9) doesn't support 'transition' (CSS3) , the submenus of the toolbar are not accessible, because they disappear immediately after you move the cursor away from the first level
That's kinda strange cause in the toolbar_megamenu.css there's a line saying
/* Fix drop-down cropping in IE 7 & 8 */
so why would they fix something for IE 7 & 8 which is not working on IE 9 ?
Or am I missing something?