Oops, not so fast.
The reason I could not see it is because it was not there !
At one point this a.m. I found one of the two 3Dsurface ops on this job had the angle param visible the other not.
I was going to point the FCStd but FC crashed, and when I reopened both were open , so not much help. It seems to be a transitory bug.
I'm guessing that since visibility gets flipped depending up on the kind of path ( line or zigzag vs the rest ) , sometimes visibility of this param is not getting set correctly.