When someone scrolls down a main menu which contains sub pop-out menus, they tend to mouse diagonally to the item they're trying to click on, instead of across and down to it. This causes the sub menu for the next item on the main menu to pop out instead, and they get frustrated. We've tried including a little instruction manual in our site's help desk - illustrated thusly:

But I still get complaints because they can't get to the items they want. Is there a way to delay the sub-menus so that the current menu will stay open longer?