Index: reactos/win32ss/user/user32/controls/scrollbar.c
===================================================================
--- reactos/win32ss/user/user32/controls/scrollbar.c	(revision 74958)
+++ reactos/win32ss/user/user32/controls/scrollbar.c	(working copy)
@@ -5,6 +5,7 @@
  * Copyright 2001 Casper S. Hornstrup
  * Copyright 2003 Thomas Weidenmueller
  * Copyright 2003 Filip Navara
+ * Copyright 2017 Katayama Hirofumi MZ
  *
  * Based on Wine code.
  *
@@ -953,6 +954,7 @@
                                                          Vertical, ScrollTrackingPos);
                 NewInfo.nTrackPos = ScrollTrackingVal;
                 NtUserSetScrollBarInfo(Wnd, IntScrollGetObjectId(SBType), &NewInfo);
+                SetScrollPos(Wnd, SBType, ScrollTrackingVal, FALSE);
                 IntScrollDrawMovingThumb(Dc, &ScrollBarInfo, Vertical);
                 SendMessageW(WndOwner, Vertical ? WM_VSCROLL : WM_HSCROLL,
                              MAKEWPARAM(SB_THUMBTRACK, ScrollTrackingVal),