{ Scroll Bar Commands }
  SB_LINEUP = 0;
  SB_LINELEFT = 0;
  SB_LINEDOWN = 1;
  SB_LINERIGHT = 1;
  SB_PAGEUP = 2;
  SB_PAGELEFT = 2;
  SB_PAGEDOWN = 3;
  SB_PAGERIGHT = 3;
  SB_THUMBPOSITION = 4;
  SB_THUMBTRACK = 5;
  SB_TOP = 6;
  SB_LEFT = 6;
  SB_BOTTOM = 7;
  SB_RIGHT = 7;
  SB_ENDSCROLL = 8;