I've got a mini-cart element that is hidden (display: none) by default. It can be revealed by clicking a "View Cart" link the navigation menu (jQuery(#mini_cart).slideDown()). Additionally, when a customer adds an item to her cart, the request is handled with AJAX, and the cart is revealed (again with slideDown).
The mini-cart is styled with an RGBA background. In most circumstances, this works great in IE8. The partially transparent background renders with no problem. However, after the AJAX call completes -- even pared down until the AJAX response does nothing -- the RGBA background disappears. Further, if I use FirebugLite to inspect the div#mini-cart element, and toggle the PIE.htc behaviour off and back on, the background reappears!
I'm at a loss to explain what bizarre way PIE and jQuery's AJAX framework are interacting to cause this.
I can provide code samples (Haml, Sass, jQuery) as needed to illustrate.
instead of toggling the cart using display:none, and display:block, try toggling it using position:absolute;top:-999em; and then you could simply remove the style attribute, $("#mini_cart").removeAttr("style")
doing this should not break the background or any other css3 effects..