Describes window/form position around screen or main form/window.

You can find more information in comments below.

enum WINDOW_POSITION // Window position
    {
        wpScreenLeftTop,
        wpScreenRightTop,
        wpScreenLeftBottom,
        wpScreenRightBottom,
        wpScreenCenter,
        wpMainFormLeftTop,
        wpMainFormRightTop,
        wpMainFormLeftBottom,
        wpMainFormRightBottom,
        wpMainFormCenter,
        wpCustom // Specified in Position member of creation params
    };