Your program has while(1) loops in it, and that interferes with the Tk event loop. It is badly written for Tk purposes, but you may be able to salvage it by putting $mw->update; in your while(1) loop, but no guarantee.

Here is the way to do it within Tk, use fileevent.

The server

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

$|=1;
$SIG{PIPE} = 'IGNORE';

my $listen = IO::Socket::INET->new(
    Proto       => 'tcp',
    LocalPort   => 7070,
    Listen      => 1,
    Reuse       => 1,
) or die "Can't create listen socket : $!\n";

my $mw = MainWindow->new();

my $text = $mw->Scrolled('Text',
                  -background =>'black',
          -foreground => 'yellow',
             )->pack();      

my $subframe = $mw->Frame()->pack();

$subframe->Button(-text => 'Clear',
         -command => sub {
                  $text->delete('1.0','end');
           })->pack(-side=>'left');

$subframe->Button(-text => 'Save Log',
         -command => sub {   })->pack(-side=>'left');

$subframe->Button(-text => 'Exit',
         -command => sub { exit  })->pack(-side=>'right');
                           
                           
$mw->fileevent($listen, 'readable', sub { new_connection($listen) });

Tk::MainLoop;

sub new_connection {
    my ($listen) = @_;
    my $client = $listen->accept() or warn "Can't accept connection";
    $client->autoflush(1);
    $mw->fileevent($client, 'readable', sub { handle_connection($clien
+t) });
    $client->print("Connected\n");
    $text->insert('end', "Connected\t");
    $text->see('end');
}

sub handle_connection {
    my ($client) = @_;
    my $message = <$client>;
    if (defined $message and $message !~ /^quit/) {
     $message =~ s/[\r\n]+$//;
     $client->print("Got message [$message]\n"); #echo back if wanted
     $text->insert('end', "Got message [$message]\t");
     $text->see('end');
    }
    else {
       $text->insert('end', "Connection Closed\n");
       $text->see('end');
       $client->close();
    }
}
[download]

A simple client ( minimally tested ) but shows the idea.

#!/usr/bin/perl
use warnings;
use strict;
use Tk;
use IO::Socket;
require Tk::ROText;

# create the socket

my $host = shift || 'localhost';
my $port = 7070;

my $socket = IO::Socket::INET->new(
       PeerAddr => $host,
       PeerPort => $port,
       Proto    => 'tcp',
      );

defined $socket or die "ERROR: Can't connect to port $port on $host: $
+!\n";

print STDERR "Connected to server ...\n";

my $mw  = new MainWindow;
my $log = $mw->Scrolled(qw/ROText -scrollbars ose/)->pack;

my $txt = $mw->Entry()->pack(qw/-fill x -pady 5/);

$mw ->bind('<Any-Enter>' => sub { $txt->Tk::focus });
$txt->bind('<Return>' => [\&broadcast, $socket]);

$mw ->fileevent($socket, readable => sub {
                    my $line = <$socket>;
                      unless (defined $line) {
                       $mw->fileevent($socket => readable => '');
                       return;
                       }
         $log->insert(end => $line);
  });


MainLoop;

sub broadcast {
    my ($ent, $sock) = @_;

    my $text = $ent->get;
    $ent->delete(qw/0 end/);

    print $sock $text, "\n";
}
[download]