Number Keypad keys not definable for keyboard shortcuts
Mac OS with Mac extended keyboard.
The numbers on the keypad are not defined by default; they do nothing when you press them. (n Mus 3 the keypad numbers did the same as the alpha numbers, and you could also define them for shortcuts.
When you try to define a keypad short cut so that 5 on the number keypad creates a quarter note, the number 5 appears when you press the key to define it, but saving the definition and then pressing the 5 key has no effect.