<oScrollBar>:hitTest( <nMouseRow>, <nMouseCol> )
        --> nHitStatus

        <nMouseRow> is a numeric value that indicates the current screen row
        position of the mouse cursor.

        <nMouseCol> is a numeric value that indicates the current screen
        column position of the mouse cursor.

        Returns a numeric value that indicates the action to perform based on
        the logical position of the mouse cursor in the scroll bar's region
        of the screen.

        Scroll Bar hittest Return Values
        ---------------------------------------------------------------------
        Value     Constant            Mouse Cursor Position
        ---------------------------------------------------------------------
        0         HTNOWHERE           Not within the scroll bar's region of
                                      the screen
        -3073     HTSCROLLTHUMBDRAG   On the thumb
        -3074     HTSCROLLUNITDEC     On the previous arrow
        -3075     HTSCROLLUNITINC     On the next arrow
        -3076     HTSCROLLBLOCKDEC    Between the previous arrow and the
                                      thumb
        -3077     HTSCROLLBLOCKINC    Between the thumb and the next arrow
        ---------------------------------------------------------------------

        Button.ch contains manifest constants for the ScrollBar:hitTest()
        return value.

        hitTest() is a method of the ScrollBar class that is used for
        determining if the mouse cursor is within the region of the screen
        that the scroll bar occupies.