The root-cause of this issue is a change of behaviour in newer versions of the Internet Explorer browser. There are both SGOS software fixes and configuration work-arounds available.
1. Enable the Pop-up Blocker in IE7 and IE8. This will make the browser more secure, so has additional benefits beyond addressing this issue.
2. Use the ICAP Trickling feature. This can be applied as the global default, or selectively using policy such as the following:
url.domain=affected_domain.com response.icap_feedback(trickle_start, 5)
In SGOS 5.4.x:
Upgrade to 18.104.22.168 or higher
In SGOS 5.5..x:
Upgrade to 22.214.171.124 or higher