Window message:
    WM_SCROLL      276    // Horizontal scroll
    WM_VSCROLL     277    // Vertical scroll

Parameters:
    SB_LINEUP      0      // Scrolls one line up. 
    SB_LINELEFT    0
    SB_LINEDOWN    1      // Scrolls one line down. 
    SB_LINERIGHT   1
    SB_PAGEUP      2      // Scrolls one page up. 
    SB_PAGELEFT    2
    SB_PAGEDOWN    3      // Scrolls one page down. 
    SB_PAGERIGHT   3
    SB_TOP         6      // Scrolls to the upper left. 
    SB_LEFT        6
    SB_BOTTOM      7      // Scrolls to the lower right.
    SB_RIGHT       7
    SB_ENDSCROLL   8      // Ends scroll. 
    
[powerscript]
//
//  Scroll Window one page down
//    WM_VSCROLL  = 277
//    SB_PAGEDOWN = 3
//
Send(Handle(this), 277, 3, 0)