禁止一个菜单而不变灰

procedure TForm1.Button1Click(Sender: TObject);
var
M: TMenu;
begin
M := Application.MainForm.Menu;
// Den ersten Menueintrag deaktivieren
// The first Item will be disabled
EnableMenuItem(M.Handle, M.Items[0].Command, MF_BYCOMMAND or MF_DISABLED);
end;