#!/usr/bin/perl

# http://perlmonks.org/?node_id=1212975

use strict;
use warnings;
use Tk;
use Tk::Pane;

my $mw = MainWindow->new;
$mw->geometry( '500x400+300+300' );

my @items;
my $selectedtext = '';

$mw->Button( -text => 'Exit', -command => sub { $mw->destroy },
  )->pack( -side => 'bottom', -expand => 0, -fill => 'x' );

$mw->Label( -textvariable => \$selectedtext,
  -width => 10,
  -font => 'courier 30', -fg => 'navy',
  )->pack( -side => 'right', -fill => 'y' );

my $pane = $mw->Scrolled(Pane => -scrollbars => 'oe',
  -sticky => 'nsew',
  )->pack(-fill => 'both', -expand => 1);

for my $text ( qw( one two three four five six seven eight nine ten ) )
  {
  my $label = $pane->Label( -text => $text,
    -anchor => 'w',
    -fg => 'red', -font => 'courier 40',
    )->pack(-fill => 'both', -expand => 1);
  push @items, $label;
  $label->bind('<ButtonRelease-1>' => sub {
    $_->configure( -fg => 'red', -font => 'courier 40' ) for @items;
    $selectedtext = $text;
    $label->configure( -fg => 'green', -font => 'times 80' );
    } );
  }

MainLoop;