Index: reactos/base/shell/explorer/settings.cpp
===================================================================
--- reactos/base/shell/explorer/settings.cpp	(revision 75228)
+++ reactos/base/shell/explorer/settings.cpp	(working copy)
@@ -2,6 +2,7 @@
  * ReactOS Explorer
  *
  * Copyright 2013 - Edijs Kolesnikovics
+ * Copyright 2017 - Katayama Hirofumi MZ
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -47,7 +48,6 @@
     TaskBarSettings.bShowClock = TRUE;
     TaskBarSettings.bAutoHide = FALSE;
     TaskBarSettings.bAlwaysOnTop = FALSE;
-
 }
 
 VOID
@@ -60,6 +60,12 @@
     
     /* FIXME: Show Clock, AutoHide and Always on top are stored in the stuckrects2 key but are not written to it with a click on apply. How is this done instead?
        AutoHide writes something to HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Desktop\Components\0 figure out what and why */
+
+    /* May the Force be with you, */
+    HWND hTrayWnd = FindWindowA("Shell_TrayWnd", NULL);
+    HWND hTrayNotifyWnd = FindWindowExA(hTrayWnd, NULL, "TrayNotifyWnd", NULL);
+    SendMessage(hTrayNotifyWnd, TNWM_SHOWCLOCK,
+                TaskBarSettings.bShowClock, TaskBarSettings.bShowSeconds);
 }
 
 BOOL
Index: reactos/base/shell/explorer/trayntfy.cpp
===================================================================
--- reactos/base/shell/explorer/trayntfy.cpp	(revision 75228)
+++ reactos/base/shell/explorer/trayntfy.cpp	(working copy)
@@ -2,6 +2,7 @@
  * ReactOS Explorer
  *
  * Copyright 2006 - 2007 Thomas Weidenmueller <w3seek@reactos.org>
+ * Copyright 2017 Katayama Hirofumi MZ <katayama.hirofumi.mz@gmail.com>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -1547,10 +1548,19 @@
     {
         BOOL PrevHidden = HideClock;
         HideClock = (wParam == 0);
+        BOOL PrevSeconds = TaskBarSettings.bShowSeconds;
+        TaskBarSettings.bShowSeconds = (lParam != 0);
 
-        if (m_clock != NULL && PrevHidden != HideClock)
+        if (m_clock != NULL &&
+            (PrevHidden != HideClock ||
+             PrevSeconds != TaskBarSettings.bShowSeconds))
         {
             m_clock->ShowWindow(HideClock ? SW_HIDE : SW_SHOW);
+
+            RECT rect;
+            GetClientRect(&rect);
+            SIZE sizClient = { rect.right, rect.bottom };
+            Size(&sizClient);
         }
 
         return (LRESULT) (!PrevHidden);