Summary: "Automatic mouse/joystick mode for mouse port"
When this option is enabled, and joystick mode is selected for port 0,
the port will automatically switch between mouse and joystick mode when
you perform joystick or mouse movement.
This is especially useful when you want to play a two-player game with
two joysticks, but need the mouse to get past cracktros or trainers. With
this option enabled, you can use both the mouse and the second joystick