my $canvas = $main->Canvas(-height => 200,
                              -width => 200,
   )->pack(-side => 'left');
   $canvas->packPropagate(0);
   my $scrollbar = $main->Scrollbar(
                           -orient => 'vertical',
                           -command => ['yview' => $canvas],
   )->pack(-fill => 'y', -side => 'right');