I'm a pianist and have a lot of neurons dedicated to finding my way around on a piano, so I made the user interface to the Music Animation Machine's performance editor almost completely controllable from a MIDI keyboard, augmented by a trackball, which is on a stand so I don't have to reach too far for it. When you're sitting at a desk in front of a computer, the natural place for a mouse or trackball is to the right of the keyboard. When you're sitting in front of a piano keyboard, that's not possible. This stand places the trackball close to the keyboard, but just slightly below, so that it doesn't interfere with playing.
At the bottom of the screen in the performance editor, you see a little one-octave keyboard graphic -- the menu:
The black notes are the main categories; when you press one of the corresponding keys on the piano keyboard, (Run is selected here), seven white-note sub-categories come up; pressing one of them brings up further sub-categories, and so on, until you've selected the operation you want. So, all the commands become little licks, which, because I'm a keyboard player, are really easy for me to learn and do -- fast!
There are a couple of nice things about this arrangement:
This setup makes editing very quick. I can move a note a little in time, then change its pitch, then change the dynamics, and change the timing of the piece, then scroll back and play it -- all very quickly.