[fix] Crash when recording on OSX

This happend only on OSX because the dynamic cast didn't work as expected. We suspect, it's because due to the proxy mechanism: The proxy are generated by paraview, and for some reason the true class cannot be identified.

requested review from @arnaud.billon

assigned to @nick.laurenson

changed the description

approved this merge request

mentioned in commit 9ce25f6a

merged