use Tk;
my $mw = MainWindow->new(-title=>"hello world");
$mw->Label(-text=>"hello")->pack();
$mw->Button(-text=>"Exit",-command=>sub{exit})->pack();
MainLoop;

##</code><code>##

use Tcl::Tk;
my $int = new Tcl::Tk;
my $mw  = $int->mainwindow;
$mw->Label( -text => "Hello World!" )->pack();
$mw->Button( -text => "Exit", -command => sub { exit } )->pack();
$int->MainLoop;

##</code><code>##

perl5.18 quit unexpectedly while using the Tk plug-in.