#!/usr/bin/perl -w
use strict;
use Tk;

my $mw = MainWindow->new(
    -title=>"Foo!",
);

my $f  = $mw->Frame(
    -width=>400,
    -height=>400,
)->pack;

$\ = "\n";

print "Tk is $Tk::VERSION; Window id is ",
      $f->winfo('id');

my $child = $mw->Toplevel(
    -title => "Bar!",
    -use => $f->winfo('id'),
);

$child->Label(
    -text=>"Bar!",
)->pack;

MainLoop();

__END__

Tk is 800.023; Window id is 0x190274

'0x190274' isn't numeric at C:/Perl/site/lib/Tk/Widget.pm line 188.
	Tk::Widget::new('Tk::Toplevel', 'MainWindow=HASH(0x1ab11dc)', '-title', 'Bar!', '-use', '0x190274') called at C:/Perl/site/lib/Tk/Widget.pm line 247
	Tk::Widget::__ANON__('MainWindow=HASH(0x1ab11dc)', '-title', 'Bar!', '-use', '0x190274') called at foy line 19