Обновление чужого окна через WinAPI

procedure Restore(Wnd: HWND);
var
  H: HWND;
begin
  H := GetWindow(Wnd, GW_OWNER);
  if (H <> 0) and IsIconic(H) then
    ShowWindow(H, SW_RESTORE);
  //SetActiveWindow(Wnd);
  SetForegroundWindow(Wnd);
end;

procedure ClickF5(Wnd: HWND);
begin
  PostMessage(Wnd, WM_KEYDOWN, VK_F5, 0);
  Sleep(100);
  PostMessage(Wnd, WM_KEYUP, VK_F5, 0);
end;

procedure TForm1.Button2Click(Sender: TObject);
var
  H: HWND;
begin
  H := FindWindow('TMainForm', nil);
  if H <> 0 then
  begin
    Restore(H);
    ClickF5(H);
    //List<IntPtr> test = GetChildWindows(H);
    // и т. д.
  end;
end;