Lines disappear in plan and section

I had some lines disappeared from plan and section at some point. The printout comes out ok but you see all
the lines of the drawing only when is selected, otherwise they disappear. Driver problem?

Hi Stefano,
Can you provide more information about this issue?
What Rhino and VisualARQ versions are you running?
Can you send a model to so we can try to reproduce this behavior?

I sent the model