use strict;
use warnings;
use Tk;

my $mw = Tk::tkinit();

my $window_1	= $mw->Toplevel(-title => 'Fenster 1');
my $window_2	= $window_1->Toplevel(-title => 'Fenster 2');

my $label	= $window_2->Label(-text => 'Vor der Suche')->pack();
$window_1->Button(-text => 'Suche', -command => sub{$label->configure(-text => 'Nach der Suche');})->pack();

$mw->MainLoop();