Wyświetlenie strony Active X w WPF WebBrowser

Chcę wyświetlić strone (Active X app) w WPF WebBrowser.

Wszystko jest dobrze gdy framevork jest .NET <=3.5 ale wymagane jest .NET >=4.0.

Otrzymuję taki błąd:

"System.InvalidOperationException: Cannot create more than one System.Windows.Application instance in the same AppDomain.\r\n at System.Windows.Application..ctor()\r\n at WebClientApp.Run_(WebClientApp* , InitializationParams* initParams)\r\n at Eagle.Application.Run(Application* , InitializationParams* )\r\n at WebClientHostControl.AppInitThread_()\r\n at System.Threading.ThreadHelper.ThreadStart_Context(Object state)\r\n at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)\r\n at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)\r\n at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)\r\n at System.Threading.ThreadHelper.ThreadStart()

<WebBrowser x:Name="WebBrowser" Source="http://xxxx:38880/webclient/index.html"/>