Added a few XBUTTON defines.
diff --git a/include/winuser.h b/include/winuser.h
index 8c6b8c9..18e618e 100644
--- a/include/winuser.h
+++ b/include/winuser.h
@@ -848,6 +848,10 @@
#define WM_NCMBUTTONUP 0x00a8
#define WM_NCMBUTTONDBLCLK 0x00a9
+#define WM_NCXBUTTONDOWN 0x00ab
+#define WM_NCXBUTTONUP 0x00ac
+#define WM_NCXBUTTONDBLCLK 0x00ad
+
/* Keyboard messages */
#define WM_KEYDOWN 0x0100
#define WM_KEYUP 0x0101
@@ -907,10 +911,12 @@
#define WM_MBUTTONUP 0x0208
#define WM_MBUTTONDBLCLK 0x0209
#define WM_MOUSEWHEEL 0x020A
-#define WM_MOUSEFIRST WM_MOUSEMOVE
+#define WM_XBUTTONDOWN 0x020B
+#define WM_XBUTTONUP 0x020C
+#define WM_XBUTTONDBLCLK 0x020D
-
-#define WM_MOUSELAST WM_MOUSEWHEEL
+#define WM_MOUSEFIRST 0x0200
+#define WM_MOUSELAST 0x020D
#define WHEEL_DELTA 120
#define WHEEL_PAGESCROLL (UINT_MAX)
@@ -2977,7 +2983,9 @@
#define VK_RBUTTON 0x02
#define VK_CANCEL 0x03
#define VK_MBUTTON 0x04
-/* 0x05-0x07 Undefined */
+#define VK_XBUTTON1 0x05
+#define VK_XBUTTON2 0x06
+/* 0x07 Undefined */
#define VK_BACK 0x08
#define VK_TAB 0x09
/* 0x0A-0x0B Undefined */
@@ -3146,6 +3154,8 @@
#define MK_SHIFT 0x0004
#define MK_CONTROL 0x0008
#define MK_MBUTTON 0x0010
+#define MK_XBUTTON1 0x0020
+#define MK_XBUTTON2 0x0040
/* Queue status flags */
#define QS_KEY 0x0001
