#!/usr/bin/perl -W
use warnings 'all';
use strict;
use Tk::Pane;     
my $mw = Tk::MainWindow->new();
my $pane = $mw->Scrolled(
  'Pane',
  -scrollbars => 'oe'
)->pack(
  -expand => 'yes',
  -fill   => 'both', # "-fill => 'y'" works, too
);

my @list;
for my $text ('A' .. 'Z') {
  my $value;
  $pane->Checkbutton(
    -anchor   => 'w',
    -text     => $text,
    -variable => \$value,
  )->pack(
    -side => 'top',
    -fill => 'x',
  );
  push @list, \$value;
}
Tk::MainLoop();

printf "%s\n", $$_||0 foreach @list;