diff --git a/win32ss/user/ntuser/winpos.c b/win32ss/user/ntuser/winpos.c
index 6c54f3c266..ff3bae698f 100644
--- a/win32ss/user/ntuser/winpos.c
+++ b/win32ss/user/ntuser/winpos.c
@@ -1653,6 +1653,67 @@ WinPosFixupFlags(WINDOWPOS *WinPos, PWND Wnd)
    return TRUE;
 }
 
+//
+// This is a HACK fix for forcing painting of non client areas.
+// Further troubleshooting in painting.c is required to remove this hack.
+// See CORE-7166 & CORE-15934
+//
+VOID
+ForceNCPaintErase(PWND Wnd, HRGN Region, PREGION Rgn)
+{
+   HDC hDC;
+   PREGION RgnUpdate;
+   UINT RgnType;
+   BOOL Create = FALSE;
+
+   if (Wnd->hrgnUpdate == NULL)
+   {
+       Wnd->hrgnUpdate = NtGdiCreateRectRgn(0, 0, 0, 0);
+       IntGdiSetRegionOwner(Wnd->hrgnUpdate, GDI_OBJ_HMGR_PUBLIC);
+       Create = TRUE;
+   }
+
+   if (Wnd->hrgnUpdate != HRGN_WINDOW)
+   {
+       RgnUpdate = REGION_LockRgn(Wnd->hrgnUpdate);
+       if (RgnUpdate)
+       {
+           RgnType = IntGdiCombineRgn(RgnUpdate, RgnUpdate, Rgn, RGN_OR);
+           REGION_UnlockRgn(RgnUpdate);
+           if (RgnType == NULLREGION)
+           {
+               IntGdiSetRegionOwner(Wnd->hrgnUpdate, GDI_OBJ_HMGR_POWNED);
+               GreDeleteObject(Wnd->hrgnUpdate);
+               Wnd->hrgnUpdate = NULL;
+           }
+       }
+   }
+
+   IntSendNCPaint(Wnd, Region); // Region can be deleted by the application.
+
+   if (Wnd->hrgnUpdate)
+   {
+       hDC = UserGetDCEx( Wnd,
+                          Wnd->hrgnUpdate,
+                          DCX_CACHE|DCX_USESTYLE|DCX_INTERSECTRGN|DCX_KEEPCLIPRGN);
+
+      Wnd->state &= ~(WNDS_SENDERASEBACKGROUND|WNDS_ERASEBACKGROUND);
+      // Kill the loop, so Clear before we send.
+      if (!co_IntSendMessage(UserHMGetHandle(Wnd), WM_ERASEBKGND, (WPARAM)hDC, 0))
+      {
+          Wnd->state |= (WNDS_SENDERASEBACKGROUND|WNDS_ERASEBACKGROUND);
+      }
+      UserReleaseDC(Wnd, hDC, FALSE);
+   }
+
+   if (Create)
+   {
+      IntGdiSetRegionOwner(Wnd->hrgnUpdate, GDI_OBJ_HMGR_POWNED);
+      GreDeleteObject(Wnd->hrgnUpdate);
+      Wnd->hrgnUpdate = NULL;
+   }
+}
+
 /* x and y are always screen relative */
 BOOLEAN FASTCALL
 co_WinPosSetWindowPos(
@@ -1862,6 +1923,13 @@ co_WinPosSetWindowPos(
 
    DceResetActiveDCEs(Window); // For WS_VISIBLE changes.
 
+   if ( Window->style & WS_VISIBLE &&
+       (WinPos.flags & SWP_STATECHANGED || (!(Window->state2 & WNDS2_WIN31COMPAT) && WinPos.flags & SWP_NOREDRAW ) ) )
+   {
+      ERR("Set WNDS_SENDNCPAINT %p\n",Window);
+      Window->state |= WNDS_SENDNCPAINT;
+   }
+
    if (!(WinPos.flags & SWP_NOREDRAW))
    {
       /* Determine the new visible region */
@@ -2029,13 +2097,19 @@ co_WinPosSetWindowPos(
 
                     if ( pwnd->style & WS_CHILD ) // Fix ProgMan menu bar drawing.
                     {
-                        TRACE("SWP_FRAMECHANGED win child %p Parent %p\n",pwnd,Parent);
+                        ERR("SWP_FRAMECHANGED win child %p Parent %p\n",pwnd,Parent);
                         pwnd = Parent ? Parent : pwnd;
                     }
 
                     if ( !(pwnd->style & WS_CHILD) )
                     {
-                        IntSendNCPaint(pwnd, HRGN_WINDOW); // Paint the whole frame.
+                        HRGN DcRgn = NtGdiCreateRectRgn(0, 0, 0, 0);
+                        PREGION DcRgnObj = REGION_LockRgn(DcRgn); 
+                        ERR("SWP_FRAMECHANGED win %p hRgn %p\n",pwnd, DcRgn);
+                        IntGdiCombineRgn(DcRgnObj, VisBefore, NULL, RGN_COPY);
+                        REGION_UnlockRgn(DcRgnObj);
+                        ForceNCPaintErase(pwnd, DcRgn, DcRgnObj);
+                        GreDeleteObject(DcRgn);
                     }
                 }
              }
@@ -2106,7 +2180,7 @@ co_WinPosSetWindowPos(
        PWND Parent = Window->spwndParent;
        if ( !(Window->style & WS_CHILD) && (Parent) && (Parent->style & WS_CLIPCHILDREN))
        {
-           TRACE("SWP_FRAMECHANGED Parent WS_CLIPCHILDREN\n");
+           TRACE("SWP_FRAMECHANGED Parent %p WS_CLIPCHILDREN %p\n",Parent,Window);
            UserSyncAndPaintWindows( Parent, RDW_CLIPCHILDREN);
        }
    }
@@ -2130,6 +2204,7 @@ co_WinPosSetWindowPos(
        {
            PWND Parent = Window->spwndParent;
            if (!Parent || UserIsDesktopWindow(Parent)) Parent = Window;
+           ERR("Erase Parent %p CHILDREN %p\n",Parent,Window);
            UserSyncAndPaintWindows( Parent, RDW_ERASENOW);
        }
 
@@ -2137,6 +2212,7 @@ co_WinPosSetWindowPos(
        if(((WinPos.flags & SWP_AGG_STATUSFLAGS) != SWP_AGG_NOPOSCHANGE)
                 && !(flags & SWP_AGG_NOCLIENTCHANGE) && (flags & SWP_SHOWWINDOW))
        {
+           ERR("Erase Window %p\n",Window);
            UserSyncAndPaintWindows( Window, RDW_ERASENOW);
        }
    }
