diff --git a/reactos/dll/win32/user32/windows/window.c b/reactos/dll/win32/user32/windows/window.c
index e794d4f016f..27b28689d9b 100644
--- a/reactos/dll/win32/user32/windows/window.c
+++ b/reactos/dll/win32/user32/windows/window.c
@@ -728,7 +728,8 @@ FindWindowExA(HWND hwndParent,
    Result = NtUserFindWindowEx(hwndParent,
                                hwndChildAfter,
                                pucClassName,
-                               pucWindowName);
+                               pucWindowName,
+                               0);
 
    if (!IS_ATOM(lpszClass) && lpszClass != NULL)
       RtlFreeUnicodeString(&ucClassName);
@@ -774,7 +775,8 @@ FindWindowExW(HWND hwndParent,
    return NtUserFindWindowEx(hwndParent,
                              hwndChildAfter,
                              pucClassName,
-                             pucWindowName);
+                             pucWindowName,
+                             0);
 }
 
 
diff --git a/reactos/include/reactos/win32k/ntuser.h b/reactos/include/reactos/win32k/ntuser.h
index 07f5047fafa..c89af68de87 100644
--- a/reactos/include/reactos/win32k/ntuser.h
+++ b/reactos/include/reactos/win32k/ntuser.h
@@ -902,7 +902,8 @@ NtUserFindWindowEx(
   HWND  hwndParent,
   HWND  hwndChildAfter,
   PUNICODE_STRING  ucClassName,
-  PUNICODE_STRING  ucWindowName
+  PUNICODE_STRING  ucWindowName,
+  DWORD dwUnknown
   );
 
 DWORD
diff --git a/reactos/subsystems/win32/win32k/ntuser/window.c b/reactos/subsystems/win32/win32k/ntuser/window.c
index 361a35340cb..4fe60245d4c 100644
--- a/reactos/subsystems/win32/win32k/ntuser/window.c
+++ b/reactos/subsystems/win32/win32k/ntuser/window.c
@@ -2464,7 +2464,8 @@ HWND STDCALL
 NtUserFindWindowEx(HWND hwndParent,
                    HWND hwndChildAfter,
                    PUNICODE_STRING ucClassName,
-                   PUNICODE_STRING ucWindowName)
+                   PUNICODE_STRING ucWindowName,
+                   DWORD dwUnknown)
 {
    PWINDOW_OBJECT Parent, ChildAfter;
    UNICODE_STRING ClassName = {0}, WindowName = {0};
diff --git a/reactos/subsystems/win32/win32k/w32ksvc.db b/reactos/subsystems/win32/win32k/w32ksvc.db
index 012aa579c11..67fca0bbda9 100644
--- a/reactos/subsystems/win32/win32k/w32ksvc.db
+++ b/reactos/subsystems/win32/win32k/w32ksvc.db
@@ -384,7 +384,7 @@ NtUserEvent                                      1
 NtUserExcludeUpdateRgn                           2
 NtUserFillWindow                                 4
 # NtUserFindExistingCursorIcon                   3  Wrong number of param ?
-# NtUserFindWindowEx                             5  Wrong number of param ?
+NtUserFindWindowEx                               5
 NtUserFlashWindowEx                              1
 NtUserGetAltTabInfo                              6
 NtUserGetAncestor                                2
@@ -678,7 +678,6 @@ NtGdiDrawStream                                  3
 # Wrong number of param ?
 NtUserEnumDisplayMonitors               5
 NtUserFindExistingCursorIcon            4
-NtUserFindWindowEx                      4
 NtUserGetClassInfo                      4
 NtUserInitTask                          11
 NtUserSetCursorIconData                 6