#!/usr/bin/perl

use warnings;
use strict;

use Tk;
use threads;
use threads::shared;

my $main = MainWindow->new();
share($main);

my $th_inc = threads->new( \&kind );

sub kind {
    $main->configure(
        -title => "Hier ist der Titel"
    );
    return 0;
}

MainLoop();

Tk::Error: Invalid value for shared scalar at C:/Perl/site/lib/Tk/After.pm line
87.
thread failed to start: Invalid value for shared scalar at C:/Perl/site/lib/Tk/W
idget.pm line 390.
 [once,[{},after#0,idle,once,[ConfigChanged,{},{}]]]
 ("after" script)