diff --git a/dlls/user32/comm16.c b/dlls/user32/comm16.c
index 46f72c6778e..072b8bd2a6c 100644
--- a/dlls/user32/comm16.c
+++ b/dlls/user32/comm16.c
@@ -63,7 +63,7 @@
 #include "windef.h"
 #include "winbase.h"
 #include "wine/winuser16.h"
-#include "win.h"
+#include "controls.h"
 #include "user_private.h"
 
 #include "wine/debug.h"
diff --git a/dlls/user32/controls.h b/dlls/user32/controls.h
index 65269c508e4..ae964b8a0e7 100644
--- a/dlls/user32/controls.h
+++ b/dlls/user32/controls.h
@@ -115,6 +115,7 @@ struct wow_handlers32
     LRESULT (*scrollbar_proc)(HWND,UINT,WPARAM,LPARAM,BOOL);
     LRESULT (*static_proc)(HWND,UINT,WPARAM,LPARAM,BOOL);
     HWND    (*create_window)(CREATESTRUCTW*,LPCWSTR,HINSTANCE,UINT);
+    HWND    (*get_win_handle)(HWND);
     WNDPROC (*alloc_winproc)(WNDPROC,BOOL);
     struct tagDIALOGINFO *(*get_dialog_info)(HWND,BOOL);
     INT     (*dialog_box_loop)(HWND,HWND);
@@ -137,6 +138,11 @@ extern void free_module_classes(HINSTANCE16) DECLSPEC_HIDDEN;
 extern void register_wow_handlers(void) DECLSPEC_HIDDEN;
 extern void WINAPI UserRegisterWowHandlers( const struct wow_handlers16 *new,
                                             struct wow_handlers32 *orig );
+static inline HWND WIN_Handle32( HWND16 hwnd16 )
+{
+    return wow_handlers32.get_win_handle( (HWND)(ULONG_PTR)hwnd16 );
+}
+
 
 /* Class functions */
 struct tagCLASS;  /* opaque structure */
diff --git a/dlls/user32/hook16.c b/dlls/user32/hook16.c
index 17d187d7aeb..cdea60f1397 100644
--- a/dlls/user32/hook16.c
+++ b/dlls/user32/hook16.c
@@ -28,7 +28,7 @@
 #include "winuser.h"
 #include "wownt32.h"
 #include "wine/winuser16.h"
-#include "win.h"
+#include "controls.h"
 #include "user_private.h"
 #include "wine/debug.h"
 
diff --git a/dlls/user32/win.c b/dlls/user32/win.c
index 393c5621747..6ce524c8861 100644
--- a/dlls/user32/win.c
+++ b/dlls/user32/win.c
@@ -524,18 +524,18 @@ HWND WIN_IsCurrentThread( HWND hwnd )
 
 
 /***********************************************************************
- *           WIN_Handle32
+ *           WIN_GetFullHandle
  *
- * Convert a 16-bit window handle to a full 32-bit handle.
+ * Convert a possibly truncated window handle to a full 32-bit handle.
  */
-HWND WIN_Handle32( HWND16 hwnd16 )
+HWND WIN_GetFullHandle( HWND hwnd )
 {
     WND *ptr;
-    HWND hwnd = (HWND)(ULONG_PTR)hwnd16;
 
-    if (hwnd16 <= 1 || hwnd16 == 0xffff) return hwnd;
+    if (!hwnd || (ULONG_PTR)hwnd >> 16) return hwnd;
+    if (LOWORD(hwnd) <= 1 || LOWORD(hwnd) == 0xffff) return hwnd;
     /* do sign extension for -2 and -3 */
-    if (hwnd16 >= (HWND16)-3) return (HWND)(LONG_PTR)(INT16)hwnd16;
+    if (LOWORD(hwnd) >= (WORD)-3) return (HWND)(LONG_PTR)(INT16)LOWORD(hwnd);
 
     if (!(ptr = WIN_GetPtr( hwnd ))) return hwnd;
 
diff --git a/dlls/user32/win.h b/dlls/user32/win.h
index ab37e3e74ab..f764d893293 100644
--- a/dlls/user32/win.h
+++ b/dlls/user32/win.h
@@ -79,7 +79,7 @@ typedef struct tagWND
 extern HWND get_hwnd_message_parent(void) DECLSPEC_HIDDEN;
 extern BOOL is_desktop_window( HWND hwnd ) DECLSPEC_HIDDEN;
 extern WND *WIN_GetPtr( HWND hwnd ) DECLSPEC_HIDDEN;
-extern HWND WIN_Handle32( HWND16 hwnd16 ) DECLSPEC_HIDDEN;
+extern HWND WIN_GetFullHandle( HWND hwnd ) DECLSPEC_HIDDEN;
 extern HWND WIN_IsCurrentProcess( HWND hwnd ) DECLSPEC_HIDDEN;
 extern HWND WIN_IsCurrentThread( HWND hwnd ) DECLSPEC_HIDDEN;
 extern HWND WIN_SetOwner( HWND hwnd, HWND owner ) DECLSPEC_HIDDEN;
@@ -98,12 +98,6 @@ extern HDESK open_winstation_desktop( HWINSTA hwinsta, LPCWSTR name, DWORD flags
 extern void USER_Lock(void) DECLSPEC_HIDDEN;
 extern void USER_Unlock(void) DECLSPEC_HIDDEN;
 
-static inline HWND WIN_GetFullHandle( HWND hwnd )
-{
-    if (!HIWORD(hwnd) && hwnd) hwnd = WIN_Handle32( LOWORD(hwnd) );
-    return hwnd;
-}
-
 /* to release pointers retrieved by WIN_GetPtr */
 static inline void WIN_ReleasePtr( WND *ptr )
 {
diff --git a/dlls/user32/winproc.c b/dlls/user32/winproc.c
index c38c0875cc1..b84abb58a32 100644
--- a/dlls/user32/winproc.c
+++ b/dlls/user32/winproc.c
@@ -1168,6 +1168,7 @@ void WINAPI UserRegisterWowHandlers( const struct wow_handlers16 *new, struct wo
     orig->scrollbar_proc  = ScrollBarWndProc_common;
     orig->static_proc     = StaticWndProc_common;
     orig->create_window   = WIN_CreateWindowEx;
+    orig->get_win_handle  = WIN_GetFullHandle;
     orig->alloc_winproc   = WINPROC_AllocProc;
     orig->get_dialog_info = DIALOG_get_info;
     orig->dialog_box_loop = DIALOG_DoDialogBox;