#!/usr/bin/perl
use strict;
use warnings;
use Cwd;
use Tk qw( MainLoop );
require Tk::ROText;

{
my $startb;
my $textbox;

my $mw = MainWindow->new(-background => 'gray50' );

my $listbox = $mw->Scrolled('Listbox',
 -font => "{Courier New} 12 bold",
 -background => 'DarkCyan',
 -foreground => 'OldLace',
 -scrollbars => 'se',
 -selectmode => "single",
    )->pack(-expand => 0, -fill => 'x');

my $pane=$mw->Scrolled('Pane',-scrollbars => 'se');

$textbox = $pane->ROText(-font => "{Courier New} 12 bold",
 -background => 'DarkBlue',
 -foreground => 'OldLace',
 -wrap => 'none',
 -height =>8
     )->pack(-expand => 0, -fill => 'x', -anchor => 'n');

$pane->pack(-expand => 1, -fill => 'x');

my $buttonFrame = $mw->Frame()->pack(-side => 'bottom', -fill=>'both', -expand=>0);

# Button to increase the height of the text box
my $growb = $buttonFrame->Button( -text    => '+',
-command => sub
{

 $textbox->packForget;
 $textbox->configure(-height => 11);
 $textbox->pack(-expand => 0, -fill => 'x', -anchor => 'n');
 $textbox->configure(-background => 'red1');
 $mw->idletasks;
 $mw->packPropagate(0);
},
)->pack(-side => "left", -fill => "both", -expand => 0);

# Button to decrease height of text box
my $shrinkb = $buttonFrame->Button( -text => '-',
-command => sub
{
 $textbox->packForget;
 $textbox->configure(-height => 6);
 $textbox->pack(-expand => 0, -fill => 'x', -anchor => 'n');
 $textbox->configure(-background => 'DarkBlue');
 $mw->idletasks;
},
)->pack(-side => "left", -fill => "both", -expand => 0);

MainLoop();
}