Tabbed Menu and IE Progress Bar

Moved to JIRA: http://sourceforge.net/tracker/index.php?func=detail&aid=1238974&group_id=48726&atid=453974

Here is the symptom we see using struts menu 2.3 and
Internet Explorer 6:

1. Click on a link that takes some time to load. Verify
the IE progress bar begins to show the progress of the
page load

2. While the load is in progress (and the original page
still visible), mouse into or out of a struts menu tabbed
menu item. The progress bar rapidly fills and then
disappears even though the new page has not come up

3. Now the original page is still in view, and there is no
progress bar activity. Eventually the new page loads, but
the user has no visible queue that the browser is
working on anything

This does not occur using the other menus - only the
tabbed menu.

Is there something in the mouseover and mouseout
event scripts that lead to the disappearance of the IE
progress bar?