Control Points dissappear?

 From:  slayer
I am modeling my helmet that I originally inquired about how to approach in the other thread that I started. Thanks for all the tips.

I have the basic shape laid out by modifying a sphere via control points. I am able to cut in half (for mirroring) and doing some other detail type work. The control -points remain available for the sphere (helmet shape) the whole time. obviously I can hide or unhide these at will. However, at some time during the model process, the control points are no longer appearing. turning these on or off does nothing.

Is this a bug or am I missing something? I have been turning control points on and off during this process and now they are gone.

Any info and/or help appreciated. Thanks.