Here is a way to do it. There may be a better way, but this is pretty foolproof.

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

my @states = qw(Alaska Hawaii Michigan Georgia Arizona Washington Oreg
+on California Texas Utah Minnesota);

my $mw = tkinit();
$mw->geometry('300x300+100+100');

my $sp = $mw->Scrolled('Pane', -scrollbars=>'osoe', sticky=>'nwse')
     ->pack(-expand=>1, -fill=>'both' );

my @cbvalues;
my @cbnames;
my $count = 0;

foreach my $d( @states){

  $cbnames[$count] = $d;

  $sp->Checkbutton(-text => $d,
        -font=>[arial => 12],
        -onvalue => 1,
        -offvalue => 0,
        -variable => \$cbvalues[$count],
        -font => 'big',
        -bg => 'white',
     )->pack(-anchor=>'w')->pack();

$count++;
}

my $showbutton= $mw->Button(-text=>'Show Selected',
-bg => 'lightyellow',
-command => sub{ 
       my @selected = ();
       foreach my $c( 0.. $count ){
            if ( $cbvalues[$c] ){
                push @selected, $cbnames[$c];
              }
         }
  
      print "@selected\n"; 
      } )->pack();

MainLoop();
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