BUG: Scrollbar Notifications Report Incorrect Position

RESOLUTION

Sample Code

   case WM_VSCROLL:
   {
      int nScrollCode = (int)LOWORD(wParam);
      int nPos = (short int)HIWORD(wParam);

      SCROLLINFO si = {sizeof(SCROLLINFO),
                       SIF_PAGE|SIF_POS|SIF_RANGE|SIF_TRACKPOS,
                       0, 0, 0, 0, 0};
      GetScrollInfo (hWnd, SB_VERT, &si);

      int nNewPos = si.nPos;

      switch (nScrollCode)
      {
         [ ... ]

         case SB_THUMBPOSITION:
            nNewPos = nPos + si.nMin;  // Adding si.nMin here
                                       // is the workaround.
            break;
      }

      si.fMask = SIF_POS;
      si.nPos = nNewPos;
      SetScrollInfo (hWnd, SB_VERT, &si, TRUE);
      return TRUE;
   }