Odd, I've not seen that. I did finally figure out that the spline is selectable. You haveto select a certain end of it. Just the endpoiint it selectable. Maybe there is a relationship there with the endpoint business.
I wonder what weird little quirks there are under the Hood of SU that are sort of forgotten or intenionally left out, but still there in code. There also used to be an "Easter Egg". It is no longer accessible, but apparently the code is still in the software.