When the settings will not respond to attempted changes, this usually indicates that the dispenser lock is engaged or the function is not being activated properly.
If the control panel is locked, the buttons will not respond when pressed, nor will the dispenser operate if in lock mode. Most displays have a lock button that can be pressed for 3-5 seconds to lock or unlock the dispenser controls.
Some functions on the display require the control button to be held for 3 or more seconds to activate or deactivate the feature. Be sure that if this is the case, the button is being held down long enough.