[Paraview] Python Render() has no effect

[Fabian Wein]

I'm still struggling with my live data reader.

A thread calls Update() on my algorithm. This leada to a RequestData()
and I give back the current data - independend of the requested time step.

It's just not displayed. I tried with python

Render()
GetRenderView().StillRender()
Show()

all has no effect. How can I do this?

Please help, I invested a week in extending my reader but this single
piece
is missing.

Thanks,

Fabian