IE hangs after lookup

Hi,
When I open and close a lookup it only works the first one or two times. Then it causes IE to hang after closing the lookup and eventually it crashes.

This happens with IE 6.0.2900.2180.xpsp_sp2_qfe.070227-2300
It doesn't happen with IE 6.0.2600.0000.xpclient.010817-1148

When I add the following code to the doUnload() function in xopus/media/lookup.html the problem doesn't seem to occur anymore:

function doUnload() {
sleep(500);
...
}

function sleep(numberMillis) {
var now = new Date();
var exitTime = now.getTime() + numberMillis;
while (true) {
now = new Date();
if (now.getTime() > exitTime)
return;
}
}

I think I'm not doing anything unusual in my lookups.

The workaround seems to solve the problem for me, but I wonder if anybody has a comment about the problem or the workaround.