Once a controller is set up as remote controller, many functionalities are disabled, mainly because the remote controller is regarded as if it’s a physical extension board wired to the main controller, so it cannot schedule zones on its own, its purpose is to passively listen to the command sent from the main controller. If it schedules zones on its own then it will lose synchronization with the main controller.
If you do want to use the program switch on the remote controller, just remove its extension mode (at the homepage, the status bar, where you see it says extension mode, click it and reset it back to normal mode). This way it can be an independent controller, so the sensors will work, but it also listen to the main controller.