For those people having problems in IE (Internet Explorer) so the overlay does not really "overlay" the dropdown boxes of their shop
the simplest solution will be to add an ID to each of the box, or a style, and in the "lightbox.js" file HIDE these elements so they does not appear at all.
E.g. for products options - encapsulate them into a <div> :
<div id="someidhere"> .... options here ... </div> and in the "lightbox.js"
near line 200 after
imgPreload.src = objLink.href;
add something like this:
document.getElementById('someidhere').style.visibility='hidden';
hope that hepls