How to remove an application from ALT + TAB?

Question

I have an app which is supposed to be hidden. To hide it from the Taskbar I use:

procedure TForm1.CreateParams(var Params: TCreateParams);
begin
  inherited;
  Params.ExStyle := Params.ExStyle and not WS_EX_APPWINDOW;
  Params.WndParent := Application.Handle;
end;

But that does not remove it from the ALT + TAB menu. How do I remove it from that menu?