Some hardware and software uses midi notes lower than what is available on the piano roll. For example my Analog Rytm uses midi notes 0-8 to trigger the drum sounds this maps on the lower end to C(-2) up but the cubase piano roll only goes down to C(0). I can work around this by using a midi effect to transpose notes down 2 octaves but it would be great if the whole midi note range was supported by default.