The problem isn't with the Listbox or Scrolled, it's with pack().

#/usr/bin/perl -w
use strict;

use Tk;

my $mw = MainWindow->new( -title => 'Test' );
my $listbox = $mw->Listbox()
            # or ->Scrolled( 'Listbox' )
                 ->pack( -expand => 1, -fill => 'both' );

my @list = ( qw ( foo bar baz batz dingo dongo dango
                  floo blar blaz blatz zingo zongo zango
                  fi ba be bz uno duo trio quitro ) );

for my $item (@list) {
    $listbox->insert( 'end', $item )    
}

MainLoop;
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