.animate, positioning, and IE7

.animate, positioning, and IE7

I am having a problem with an absolutely-positioned div disappearing while IE7 is animating.  The animation has a z-index lower than the div containing Questions, Customizable, and Library, but the div disappears during animation.  Is there anything I can do about this?  I've tried changing the positioning, z-index, and moving the div to occur before the animation, but nothing seems to work.  Everything looks fine in FF, IE8, and Safari.