The KeyUp event occurs when a key is released.
void KeyUp( short nKeyCode, short nShiftState );
[in] Specifies which physical key is released. For possible values, see the Remarks section of the KeyDown event.
[in] A bit field with the least significant bits corresponding to the SHIFT key (bit 0), the CTRL key (bit 1), and the ALT key (bit 2). These bits correspond to the values 1, 2, and 4, respectively. The shift argument indicates the state of these keys. Some, all, or none of the bits can be set, indicating that some, all, or none of the keys are pressed.