Determines the positioning of the check box relative to the area of this object. Possible values for this property are 1- rv2TopLeft: Aligned top and left, 2 - rv2TopCenter: Aligned top and center, 4 - rv2TopRight: Aligned top and right, 16 - rv2MIddleLeft: Aligned top and left (default), 32 - rv2MiddleCenter: Aligned to center, 64 - rv2MiddleRight: Aligned center and right, 256 - rv2BottomLeft: Aligned bottom and left, 512 - rv2BottomCenter: Aligned bottom and center, or 1024 - BottomRight: Aligned bottom and right.