QlikView application is dimmed in browser, instead of showing the expected dialog. The client appears unresponsive to any user interaction.
This issue does not appear if QlikView Web Server is used, it only appears with IIS as web server.
The issue is caused by IIS configuration of X-Frame-Options HTTP response header. This configuration is part of mitigating the website from Clickjacking attacks, as you can see in Potential ClickJacking Vulnerability
In the scenario when this issue happens, a HTML iframe element is used in the QlikView dialog, and IIS is blocking it by having X-Frame-Options HTTP response header set to DENY. This can be revealed by analyzing HTTP traffic trace or by using browser developer tools to verify console output.
The issue can be resolved by changing IIS configuration of X-Frame-Options HTTP response header to SAMEORIGIN, as described in Microsoft's KB2694329
Note, please consult the local web server administrator before changing this security related configuration on IIS.