Drawing in Perspective

I’ve been retired for a number of years and I’m just returning to Rhino (v5)

I’m amazed how much I’ve forgotten and how quickly it’s coming back to me. One thing has me puzzled.

I think I used to be able to create geometry in the perspective viewport, using osnapss and not have everything snap to the current cPlane.

What’s the “secret”?

Two possibilities:
Project Osnap is turned on. Anything drawn will be projected onto the Cplane.
Planar is turned off. With Planar turned off any “clicks” which are not snapped to an object will be on the Cplane.

Thx. It was ProjectOsnap.