Yes, that would be very(!) helpful. Problem without is that you have to press the sustain button 2times with the foot. And this often fails and brings you out of the concept in a live context . That is very stressing: when you realize that sustain is off, it is too late. The small sustain symbol is so small so that you cannot see it out of the corner of the eye. A no-chord would be very important feature, as it would be the only possibility be to STOP with one footpress.