[jQuery] Parent window grabs focus from popup in IE

[selfsimilar]

I'm using the Autocomplete plugin and chaining some actions to the
result. One of these actions is a popup, and the popup maintains focus
under FF, but under IE the parent window grabs focus back when the
form input is finally updated at the end of the chain by autocomplete.
Example code:
----------------------------
<form>
<input type="text" id="vendor" name="vendor />
<input type="hidden" id="VendoID" name="VendorID" />
</form>

<script type="text/javascript">
<!--
$(document).ready(function(){
  $("#vendor").autocomplete("search/vendors.php", {
    matchContains: true,
    mustMatch: true,
    minChars: 0,
    width: 350,
    max:1000,
    scrollheight: 350
  });
  $("#vendor").result(function(event, data, formatted) {
    if (data) {
      $("#VendorID").val(data[1]);
      popup('pop_select_vendor_contact.php?vid=' + $("#VendorID").val
());
    }
  });
});
// -->
</script>
----------------------------

I've also tried moving the call to the popup to the 'change' event for
both 'vendor' and 'vendorID', but neither get triggered. I've tried
manually triggering the 'change' event where the current call to
'popup' is, but the focus problem remains.

Is there another event I can listen for? Some other way to structure
this?

Thanks,
Colin