Réduire le menu système

procedure TForm1.Button1Click(Sender:TObject);
var
handle: THandle;

begin
handle:=GetSystemMenu(Self.Handle,false);
RemoveMenu(handle, 8, mf_byposition);
RemoveMenu(handle, 7, mf_byposition);
RemoveMenu(handle, 6, mf_byposition);
RemoveMenu(handle, 5, mf_byposition);
end;