This System option in Options Configuration determines how the minus key (-) on the numeric keypad works. Normally this key is used by Eagle for Windows as a function key to display the Misc menu. Setting this option to N allows the key to be used as a minus sign. If you do set this option to N, you will access the Misc menu via the Action menu, via clicking the Misc toolbar button with your mouse, or by pressing Ctrl and / (forward slash) together.