[Paraview] Level of Detail (LOD) significantly slower in PV3.9.0 compared to PV3.8.1

[Utkarsh Ayachit]

> however from the coarse view back to the detailed one pv 3.9.0 is about
> factor of 2-4 slower compared to pv 3.8.1.

ParaView 3.9 has a feature which can be turned off by the user using
the Setting dialog which results in ParaView delaying the switch back
from Interactive render by a few seconds. You should be seeing a
"countdown" in the status bar as that starts happening. Within this
time, user can start interaction again thus avoid having to wait for
fullres render when doing continuous adjustments to the camera.

If you don't want it, turn if off by using Edit | Settings dialog and
then on the Render View page, set "Lock Interactive Render" slider to
0.

Utkarsh