#!/usr/bin/perl
use warnings;
use strict;
use Tk;
use Tk::LabFrame;

my $mw = tkinit;
                             
my $lframe = $mw->LabFrame(-label=>"New",
                -labelside=>'acrosstop')->pack;
                             
my $listn = $lframe->Scrolled(qw/Listbox -foreground red -selectforeground blue/)->pack;
                             
my @allevents =( 1..100);
foreach my $key (@allevents) {
  $listn->insert('end', $key);
}

$mw->Button(-text => "Add to Listbox",
            -command=> sub{
                 $listn->insert('end', 'foobar');
                 $listn->see('end');
                      })->pack;

MainLoop;