It looks to me that when I cut a section, it permanently alters the model. And, it doesn't remember what the model was.
So, sections must be done on duplicates of the model in order to retain the ability to continue working with the model.
I'm surprised to see this approach. Maybe, I'm missing something? Would not be the first time.
I see that I can keep the model objects if I ghost or keep operands. Is the the route to retaining the model? Keeping them results in overlay confusion. Ghosting allows me to keep them visually separate, but then the model I want might intermingle with other ghosts I do not want to unghost with the model.