diff --git a/mingw-w64-headers/include/ChangeLog b/mingw-w64-headers/include/ChangeLog
index ca2571c..410ef58 100644
--- a/mingw-w64-headers/include/ChangeLog
+++ b/mingw-w64-headers/include/ChangeLog
@@ -1,3 +1,7 @@
+2012-02-01  Kai Tietz  <ktietz@redhat.com>
+
+	* shobjidl.h (THBN_CLICKED): Define constant.
+
 2012-01-29  Jonathan Yong  <jon_y@users.sourceforge.net>
 
 	* strsafe.h (MPRAPI_OBJECT_HEADER): Fix double extern qualifier in
diff --git a/mingw-w64-headers/include/shobjidl.h b/mingw-w64-headers/include/shobjidl.h
index 6fd94c5..2d918bc 100644
--- a/mingw-w64-headers/include/shobjidl.h
+++ b/mingw-w64-headers/include/shobjidl.h
@@ -3054,6 +3054,8 @@
 typedef struct THUMBBUTTON *LPTHUMBBUTTON;
 #include <poppack.h>
 
+#define THBN_CLICKED 0x1800
+
 /*****************************************************************************
  * ITaskbarList3 interface
  */