MX Menubar Not Collapsing?

I've got a rollover menu bar of buttons that opens up a list of sub-items below each button when you roll over it. Pretty standard, right? Then once that movie plays (sub-items appearing), a thin box appears both around those items and the menu bar's actual button, meaning that once the mouse pointer moves off of either the button of the sub-items, the movie disappears (that's what my invisible button is set to do). And herein lies my problem.

While the button works almost always, if I drag the mouse pointer very quickly over the active area, the button fails to activate. So I can literally keep my pointer at one side of the screen and race it over to the other side, activating all the sub-menus and making them stick in their 'open' position. Someone on these forums suggested increasing my framerate and I've set this to maximum. It makes the problem less frequent, but doesn't fix it. This problem happens both in the preview window and my browser (Firefox, Vista).So I guess at this point I either need a way to 1) Fix the problem and make them close, either by tweaking what I already have or making a rollover menu by a different means or2) Add something to each item like a 'timeout', where if there's no pointer present for, say, 1 sec, the it closes automatically. But I don't know if such a thing exists, especially in an older version like MX.