On Mac OS X, F1 through F4 are reserved for Undo, Cut, Copy, and Paste, respectively. Unfortunately we can’t change those settings. So if you assign one of those keys to a snippet or a shortcut, what happens when you press the key is, first, Mac OS triggers the underlying editing action, and second, InqScribe senses the keypress and triggers the snippet or shortcut. Generally, this is not what you want, so we recommend avoiding F1 through F4 on Mac OS X.