Boy, that was a long slog ... BUT IT'S FINALLY WORKING!! Base and slider can be placed and moved independently. Was in a tailspin for awhile, but backed-up to the last-known-good version in Git, then iterated baby-step by baby-step. See the description in my Trello for, "Make the virtual slider button movable" for an account of the whole slog.
Log in or sign up for Devpost to join the conversation.