While making a WCF Web Service, I came across a problem while using a method with a webbrowser control. The method starts a thread and uses a webbrowser control to fill in some forms and click further, waiting for a event handler to fire and return a answer I need. The method is tested and works within its own enviroment, but used in a WCF Web Service enviroment, the event handlers just won't fire. A result of that is the waiting manualresetevent not ending. Is this because of the new thread or because of the bad event handling of the web service? If yes, what is a reasonable solution?