Background image from parent div sliding in with child div (IE only)

Background image from parent div sliding in with child div (IE only)


I am not quite sure why this is happening.
http://www.rooxilist.com/bbnlev/innovation.html
Working on this site for a client. The right hand div, #content, is
set up to slide in from the right the first time you hit the page. In
IE it slides in all correct like, but so does the background image of
the parent div, #bgfield. WTF? The jquery object is never even
attached to #bgfield!!! At first I was confused because it worked fine
on the PC I use for testing (not sure why?!?). She sent me a screen
shot showing the action mid-slide in IE7.
Firefox, etc. is perfectly happy.
external css looks like this:
#bgfield {
    position: relative;
    width: 900px;
    height: 448px;
    border: solid 10px #FFFFFF;
    /* background-image: url(images/transparent.gif); -- override this
for each page */
    background-position: center top;
    background-repeat: no-repeat;
    background-attachment: scroll;
    text-align: center;
    padding-top: 112px;
    overflow: hidden;
}
and
#bgfield #content {
    float: right;
    position: relative;
    background-attachment: scroll;
    background-image: url(../images/rightbg87pc.png);
    background-position: right top;
    background-repeat: no-repeat;
    overflow: hidden;
    height: 275px;
    width: 651px;
    text-align: left;
    font-family: Arial, Helvetica, sans-serif;
    color: #000000;
    margin-right: 0px;
}
with local overrides as appropriate for each version of the page.
My jquery script has this:
$("#content").css({'margin-right' : '-651px' }).animate
( { marginRight: "0px" }, 1200 );
Any ideas? I've been futzing around with the css, trying other tweaks
and a couple hacks (some of which are still there)... apparently it's
still a problem.
S.