That would imply that you have a way to give the icon Focus. To my knowledge this is not possible with the standard NotifyIcon class. If something does not have focus then it will not respond to keyboard events (and this class doesn't have the normal keyboard event handlers anyway).

You'd have to come up with a way of globally scanning the keyboard states in another process or by using a timer.

In short, you can't. Unless you go out of your way to modify the NotifyIcon class.