Thank you, Scott, that worked perfectly. As an aside, JMP Help said they will be putting (returning?) the functionality into the sidebar menu. If I'm reading their reply correctly, seems this used to work, but maybe got inadvertently dropped in some recent releases.
As a nitpick, I had looked previously at performing the steps you showed. To me, it read as dropping the "Fit", which I read as the Line of Fit. Maybe if it had been labeled as "Fit Interval", I would have understood that it would not erase the Fit Line, but the CI around the Fit Line.
Thanks again for investigating this. JMP Community is remarkably helpful. Regards, Paul