Dear Utkarsh,
Thank You very much for Your help. I hope Sebastien will have some idea.
Btw, in a meantime, I discovered one interesting detail. If I set
pipeline source (with widget) as currently active source
(SetActiveSource(...) in pvpython) before I execute code I mentioned
in first message
Glad to hear that it's working. As for the parallel test failure, I think
you can ignore that for now. I need to fix it but I just haven't gotten
around to it yet. I think it's either a parallel rendering/compositing
issue or a problem with the actors's visibility in the views getting
screwed up.