[Paraview] PV in client-server mode: external window "Visualization Toolkit: OpenGL"?

[Peter J. Bismuti]

When I try and run PV in client-server mode I get a window that pops up that 
has a title "Visualization Toolkit - OpenGL".  At times it appears that the 
graphics is being rendered in this window, but it is very confusing as this 
window and the normal graphics window go blank very easily and take quite a 
while to redraw.  

Is this normal? 

Thanks