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

my %top_hash;

share $top_hash{'A'}{'B'};
$top_hash{'A'}{'B'} = 'Original';

my $t = MainWindow->new()->Scrolled('Text')->pack();
my $e = $t->Entry(-textvariable => \$top_hash{'A'}{'B'});
$t->windowCreate('end', -window => $e);
$t->insert('end', "\n");

my $timer = $t->after(3000,sub{$top_hash{'A'}{'B'} = 'Changed'});

MainLoop;