[PyMOL] Cylindrical helices don't show up

[HJ L. <hoj...@gm...>]

For some reasons, PyMOL (1.6.0.0, windows 64 bits) doesn't show the cylindrical helices in cartoon presentation. It just presents helices as an empty space when the cylindrical helices option is ON . Regular helix representation works well. 

That would be really great if anyone could give me a clue how to fix it. 

Many thanks

HJ