You're right. Switching off the display has the same effect.
Next question: can I configure the display of my three M devices differently depending on the chosen source? Would be nice. For example when I use the tuner of my G68 I want to switch off the display of my G91A (which shows the not-used G91A tuner). But I'm pretty sure that's not configurable yet.
BTW and OT, Ian, looking at your signature: you have a nice 5.1 DSP setup but which device is feeding it? Does the F80 output 5.1?
Regards,
Rupert