At least show the window when wParam is TRUE and the window is currently
invisible

reactos/lib/user32/windows

diff -u -r1.146 -r1.147
--- defwnd.c	12 Sep 2004 19:47:49 -0000	1.146
+++ defwnd.c	19 Nov 2004 23:07:09 -0000	1.147
@@ -1,4 +1,4 @@

-/* $Id: defwnd.c,v 1.146 2004/09/12 19:47:49 weiden Exp $

+/* $Id: defwnd.c,v 1.147 2004/11/19 23:07:09 gvg Exp $

  *
  * COPYRIGHT:       See COPYING in the top level directory
  * PROJECT:         ReactOS user32.dll

@@ -272,6 +272,11 @@

 VOID
 DefWndSetRedraw(HWND hWnd, WPARAM wParam)
 {

+  if ((BOOL) wParam && 0 == (GetWindowLong(hWnd, GWL_STYLE) & WS_VISIBLE))
+    {
+      ShowWindow(hWnd, SW_NORMAL);
+    }
+

   UNIMPLEMENTED;
 }