title: System.Windows.Forms.WebBrowser sometimes does NTLM auth - why?
body: <p>I have a Windows Forms app targeting .NET 2.0.  I'm attempting to add a single sign-on feature via the SAML 2.0 protocol, for which the most efficient apparent solution was an embedded web browser.</p>
  
  <p>I've verified using a dummy app containing only a WebBrowser control that the NTLM exchange does take place.  However, when I embed apparently the same control into the larger application, the browser doesn't respond to the initial HTTP 401 challenge and instead redirects to IE's "Navigation Canceled" page.</p>
  
  <p>The Googles have not been forthcoming, and I'm puzzled at this behavior.  Can anyone shed some light on what might be inhibiting the WebBrowser's credential negotiation?</p>