Params Between Parent And Popup Windows Using IE (everything's Fine With Firefox)

I have one page with <select> list in it, which opens a popup with
another <select> list. Those two list are linked... When I select
something in the list that is in popup window and confirm the selection
(by pressing button), I call a function that fills the "parent" window
and forces popup to close. All this is accomplished by directly
accessing another list:

for(var i = 0; i <= selLength; i++){
name = parent.window.opener.listValues.options[i].text;
value = parent.window.opener.listValues.options[i].value;

self.document.form1.itemList.options[i] = new Option(name, value);
}

And this doesn't seem to work with IE. With Firefox is OK.

Any ideas how to make it work with IE?