diff --git a/reactos/dll/win32/user32/windows/paint.c b/reactos/dll/win32/user32/windows/paint.c
index 982cc5cfb06..6ea4a478c71 100644
--- a/reactos/dll/win32/user32/windows/paint.c
+++ b/reactos/dll/win32/user32/windows/paint.c
@@ -278,7 +278,7 @@ GetWindowRgn(
 
   pWnd = ValidateHwnd(hWnd);
 
-  if (!pWnd) // || !pwnd->hrgnClip || pwnd->state2 & WNDS2_MAXIMIZEDMONITORREGION)
+  if (!pWnd) // || !pWnd->hrgnClip || pWnd->state2 & WNDS2_MAXIMIZEDMONITORREGION)
      return ERROR;
 /*
   Ret = CombineRgn(hRgn, pWnd->hrgnClip, NULL, RGN_COPY);
@@ -314,21 +314,19 @@ GetWindowRgnBox(
 
   pWnd = ValidateHwnd(hWnd);
 
-  if (!pWnd) // || !pwnd->hrgnClip || pwnd->state2 & WNDS2_MAXIMIZEDMONITORREGION)
+  if (!pWnd || !pWnd->hrgnClip || pWnd->state2 & WNDS2_MAXIMIZEDMONITORREGION)
      return ERROR;
-/*
+
   Ret = GetRgnBox(pWnd->hrgnClip, lprc);
 
   if (!Ret)
      return ERROR;
 
   if (pWnd->fnid != FNID_DESKTOP)
-     Ret = OffsetRect(lprc, -pWnd->rcWindow.left, -pWnd->rcWindow.top);
+     OffsetRect(lprc, -pWnd->rcWindow.left, -pWnd->rcWindow.top);
 
   if (pWnd->ExStyle & WS_EX_LAYOUTRTL)
      MirrorWindowRect(pWnd, lprc);
-*/
-  Ret = (int)NtUserCallTwoParam((DWORD_PTR)hWnd, (DWORD_PTR)lprc, TWOPARAM_ROUTINE_GETWINDOWRGNBOX);
 
   return Ret;
 }
diff --git a/reactos/include/reactos/win32k/ntuser.h b/reactos/include/reactos/win32k/ntuser.h
index 0b4f587a34a..5610bf94e7f 100644
--- a/reactos/include/reactos/win32k/ntuser.h
+++ b/reactos/include/reactos/win32k/ntuser.h
@@ -3130,7 +3130,6 @@ typedef struct tagKMDDELPARAM
 #define ONEPARAM_ROUTINE_ENABLEPROCWNDGHSTING 0xfffe000d
 #define ONEPARAM_ROUTINE_GETDESKTOPMAPPING    0xfffe000e
 #define ONEPARAM_ROUTINE_GETCURSORPOSITION    0xfffe0048 // use ONEPARAM_ or TWOPARAM routine ?
-#define TWOPARAM_ROUTINE_GETWINDOWRGNBOX    0xfffd0048 // user mode
 #define TWOPARAM_ROUTINE_GETWINDOWRGN       0xfffd0049 // user mode
 #define TWOPARAM_ROUTINE_SETMENUBARHEIGHT   0xfffd0050
 #define TWOPARAM_ROUTINE_SETGUITHRDHANDLE   0xfffd0052
diff --git a/reactos/subsystems/win32/win32k/ntuser/simplecall.c b/reactos/subsystems/win32/win32k/ntuser/simplecall.c
index f31b44296a1..155feeda3fc 100644
--- a/reactos/subsystems/win32/win32k/ntuser/simplecall.c
+++ b/reactos/subsystems/win32/win32k/ntuser/simplecall.c
@@ -367,7 +367,6 @@ NtUserCallTwoParam(
    DWORD_PTR Param2,
    DWORD Routine)
 {
-   NTSTATUS Status;
    PWND Window;
    DECLARE_RETURN(DWORD_PTR);
 
@@ -376,22 +375,6 @@ NtUserCallTwoParam(
 
    switch(Routine)
    {
-      case TWOPARAM_ROUTINE_GETWINDOWRGNBOX:
-         {
-            DWORD_PTR Ret;
-            RECTL rcRect;
-            Window = UserGetWindowObject((HWND)Param1);
-            if (!Window) RETURN(ERROR);
-
-            Ret = (DWORD_PTR)IntGetWindowRgnBox(Window, &rcRect);
-            Status = MmCopyToCaller((PVOID)Param2, &rcRect, sizeof(RECT));
-            if(!NT_SUCCESS(Status))
-            {
-               SetLastNtError(Status);
-               RETURN( ERROR);
-            }
-            RETURN( Ret);
-         }
       case TWOPARAM_ROUTINE_GETWINDOWRGN:
          {
             Window = UserGetWindowObject((HWND)Param1);
diff --git a/reactos/subsystems/win32/win32k/ntuser/window.c b/reactos/subsystems/win32/win32k/ntuser/window.c
index cb431f21000..321666e362f 100644
--- a/reactos/subsystems/win32/win32k/ntuser/window.c
+++ b/reactos/subsystems/win32/win32k/ntuser/window.c
@@ -4056,45 +4056,6 @@ IntGetWindowRgn(PWND Window, HRGN hRgn)
    return Ret;
 }
 
-// This should be in user32!
-INT FASTCALL
-IntGetWindowRgnBox(PWND Window, RECTL *Rect)
-{
-   INT Ret;
-   HRGN VisRgn;
-   ROSRGNDATA *pRgn;
-
-   if(!Window)
-   {
-      return ERROR;
-   }
-   if(!Rect)
-   {
-      return ERROR;
-   }
-
-   /* Create a new window region using the window rectangle */
-   VisRgn = IntSysCreateRectRgnIndirect(&Window->rcWindow);
-   NtGdiOffsetRgn(VisRgn, -Window->rcWindow.left, -Window->rcWindow.top);
-   /* if there's a region assigned to the window, combine them both */
-   if(Window->hrgnClip && !(Window->style & WS_MINIMIZE))
-      NtGdiCombineRgn(VisRgn, VisRgn, Window->hrgnClip, RGN_AND);
-
-   if((pRgn = RGNOBJAPI_Lock(VisRgn, NULL)))
-   {
-      Ret = REGION_Complexity(pRgn);
-      *Rect = pRgn->rdh.rcBound;
-      RGNOBJAPI_Unlock(pRgn);
-   }
-   else
-      Ret = ERROR;
-
-   REGION_FreeRgnByHandle(VisRgn);
-
-   return Ret;
-}
-
-
 /*
  * @implemented
  */
@@ -4143,6 +4104,12 @@ NtUserSetWindowRgn(
       GreDeleteObject(Window->hrgnClip);
    }
 
+   if (Window->fnid != FNID_DESKTOP)
+      NtGdiOffsetRgn(hrgnCopy, Window->rcWindow.left, Window->rcWindow.top);
+
+   /* Set public ownership */
+   IntGdiSetRegionOwner(hrgnCopy, GDI_OBJ_HMGR_PUBLIC);
+
    Window->hrgnClip = hrgnCopy;
 
    Ret = co_WinPosSetWindowPos(Window, HWND_TOP, 0, 0, 0, 0, bRedraw ? flags : (flags|SWP_NOREDRAW) );