diff --git a/reactos/lib/gdi32/misc/gdientry.c b/reactos/lib/gdi32/misc/gdientry.c
index 9ee0a847796..7cc66332d9d 100644
--- a/reactos/lib/gdi32/misc/gdientry.c
+++ b/reactos/lib/gdi32/misc/gdientry.c
@@ -191,3 +191,16 @@ DdReenableDirectDrawObject(LPDDRAWI_DIRECTDRAW_GBL pDirectDrawGlobal,
 
   return NtGdiDdReenableDirectDrawObject((HANDLE)pDirectDrawGlobal->hDD, pbNewMode); 	
 } 
+
+/*
+ * @implemented
+ *
+ * GDIEntry 12
+ */
+VOID STDCALL DdUnattachSurface( 
+LPDDRAWI_DDRAWSURFACE_LCL pSurface,
+LPDDRAWI_DDRAWSURFACE_LCL pSurfaceAttached
+)
+{
+  NtGdiDdUnattachSurface((HANDLE) pSurface->hDDSurface, (HANDLE) pSurfaceAttached->hDDSurface);	
+}
diff --git a/reactos/lib/gdi32/misc/stubs.c b/reactos/lib/gdi32/misc/stubs.c
index 8e0c15623d2..b01a862168e 100644
--- a/reactos/lib/gdi32/misc/stubs.c
+++ b/reactos/lib/gdi32/misc/stubs.c
@@ -3937,17 +3937,7 @@ LPDDRAWI_DDRAWSURFACE_LCL pSurfaceTo
 	return 0;
 }
 
-/*
- * @unimplemented
- */
-VOID STDCALL DdUnattachSurface( 
-LPDDRAWI_DDRAWSURFACE_LCL pSurface,
-LPDDRAWI_DDRAWSURFACE_LCL pSurfaceAttached
-)
-{
-	UNIMPLEMENTED;
-	SetLastError(ERROR_CALL_NOT_IMPLEMENTED);
-}
+
 
 /*
  * @unimplemented