ActiveX control and pick problem

I have a strange problem where I have picking code that works under a Win32/MFC application, but doesn’t work in an ActiveX control environment. General rendering works fine, but when I try to pick something, the following routine:

glGetIntegerv( GL_VIEWPORT, viewport );

does NOT set the viewport array!!! Even if I hardcode the viewport array, picking still doesn’t work, so I suspect something is afoot in the OpenGL subsystem. But what?

Has anyone ever got picking to work under an ActiveX control window? Any ideas?

Thanks very much in advance,