diff --git a/include/winuser.h b/include/winuser.h
index af1b9cb..e39ddff 100644
--- a/include/winuser.h
+++ b/include/winuser.h
@@ -2585,6 +2585,22 @@
 #define HWND_NOTOPMOST      ((HWND)-2)
 #define HWND_MESSAGE        ((HWND)-3)
 
+/* GetDCEx flags */
+#define DCX_WINDOW           0x00000001
+#define DCX_CACHE            0x00000002
+#define DCX_NORESETATTRS     0x00000004
+#define DCX_CLIPCHILDREN     0x00000008
+#define DCX_CLIPSIBLINGS     0x00000010
+#define DCX_PARENTCLIP       0x00000020
+#define DCX_EXCLUDERGN       0x00000040
+#define DCX_INTERSECTRGN     0x00000080
+#define DCX_EXCLUDEUPDATE    0x00000100
+#define DCX_INTERSECTUPDATE  0x00000200
+#define DCX_LOCKWINDOWUPDATE 0x00000400
+#define DCX_USESTYLE         0x00010000
+#define DCX_NORECOMPUTE      0x00100000
+#define DCX_VALIDATE         0x00200000
+
 #define MF_INSERT          0x0000
 #define MF_CHANGE          0x0080
 #define MF_APPEND          0x0100