Starting in WPF 4, the ClickOnce elevation prompt is also
enabled for XAML Browser Applications (XBAPs) in Intranet and Trusted Zones,
making it easier to deploy full-trust XBAPs. For XBAPs that require security
permissions greater than the minimum code access security (CAS) permission
grantset of the Intranet and Trusted Zones, the user will be able to click
'Run' on the ClickOnce elevation prompt when they navigate to the XBAP to allow
the XBAP to run with the requested permissions.