In a VB plug-in, this call works fine to invoke the PV preview window:

status = swRayTraceRenderer.DisplayPreviewWindow

In a C# plug-in, the same call does nothing.

status = swRayTraceRenderer.DisplayPreviewWindow();

I appear to have a good/valid swRayTraceRenderer object.  Initialized like so:

swRayTraceRenderer = (RayTraceRenderer)iSwApp.GetRayTraceRenderer((int)swRayTraceRenderType_e.swPhotoView);

PV is added in and can be invoked manually.

I'm stumped.  Why would it work in VB and fail in C#???