my $menubar = $main->Menu(-type => 'menubar');
$main->configure(-menu => $menubar);
my $menu_links = $menubar->cascade(-label => "Links", -tearoff => 0);
$menu_links->command(-label => 'test1', -command => \&sub1);
$menu_links->command(-label => 'test2', -command => \&sub2);
$menu_links->command(-label => 'test3', -command => \&sub3);
……