Specifies whether the scroll bar is a control or part of a window's nonclient area. If it is part of the nonclient area, nBar also indicates whether the scroll bar is positioned horizontally, vertically, or both. It must be one of the following:
SB_BOTH Specifies the horizontal and vertical scroll bars of the window.
SB_HORZ Specifies that the window is a horizontal scroll bar.
SB_VERT Specifies that the window is a vertical scroll bar.
Specifies whether Windows shows or hides the scroll bar. If this parameter is TRUE, the scroll bar is shown; otherwise the scroll bar is hidden.