Index: reactos/win32ss/user/user32/controls/scrollbar.c
===================================================================
--- reactos/win32ss/user/user32/controls/scrollbar.c	(revision 74920)
+++ reactos/win32ss/user/user32/controls/scrollbar.c	(working copy)
@@ -955,7 +955,7 @@
                 NtUserSetScrollBarInfo(Wnd, IntScrollGetObjectId(SBType), &NewInfo);
                 IntScrollDrawMovingThumb(Dc, &ScrollBarInfo, Vertical);
                 SendMessageW(WndOwner, Vertical ? WM_VSCROLL : WM_HSCROLL,
-                             MAKEWPARAM(SB_THUMBTRACK, ScrollTrackingVal),
+                             MAKEWPARAM(SB_THUMBPOSITION, ScrollTrackingVal),
                              (LPARAM) WndCtl);
              }
         }