IE Hangs when closing Report Viewer

I have .Net web application running on IIS 7.5 with Crystal Report runtime 13.0.14.

Whenever I use a browser to view a report and close the report viewer, the IE hangs, this only happens in Citrix environment XenApp 6.5 which is running on Windows Server 2008 R2.  No error if I use a browser in Windows 7 or remote desktop to the windows server.

Please help.