[Feature] Partial-trust applications [Recommended changes] In your browser applications, you can ease this change by doing one of the following: Run the browser application in full trust. Have customers add the application's site to the trusted sites zone. Have customers run the application in Internet Explorer. [Differences from 3.5 SP1] 
For security considerations, Windows-based applications that run in partial trust and contain a WebBrowser control or a Frame control that contains HTML will throw a SecurityException when the control is created. Browser applications will throw an exception and display a message if all of the following conditions are met: The application is running in Firefox. The application is running in partial trust in the Internet zone from non-trusted sites. The application contains a WebBrowser control or a Frame control that contains HTML Note that applications that run from trusted sites or from the intranet zone will not be affected.