Will any IE security setting prevent access to WebBrowser's ObjectForScripting?

I have an application that sets a WebBrowser's ObjectForScripting property to a custom object so that the user can access it from javascript code using window.exte开发者_如何学Gornal. It have always worked fine but now one of my customers seems unable to access it.

I cannot be 100% sure what the problem is because I'd have to access his computer and I don't want to bug him that much since he's a customer and seems like he found a workaround to what he was trying to do. But it seems to me like he cannot access the object at window.external.

Other than unchecking Active Scripting (which doesn't actually prevents access to window.external), do you know any security setting that will prevent access to the object at window.external?

make sure the external object is safe or allowed for scripting.