use strict;
use Tk;

my $main = MainWindow->new;

my $list = $main->Scrolled('Listbox', -scrollbars => 'e',
                           -selectmode => 'single')->pack;

foreach my $i (1..100) {
   $list->insert('end', "item $i");
}

my $button = $main->Button(-text => "Scroll to Bottom of List",
                           -command => \&scroll_to_bottom)->pack;
MainLoop;

sub scroll_to_bottom {
   $list->see('end');#make the last element viewable
}