my $gv = $root->Scrolled('GraphViz', 
                             -background => '#B0C0FF', 
                             -scrollbars=>'se',
                             ) ->pack (-side=>'top',-expand 
                                        =>1, -fill=>'both');

##</code><code>##

my $canvas = $gv->Subwidget("canvas');
$canvas->bind('<Configure>', sub {
                                  my $w = shift;
                                  print $w->Width . " and " . $w->Height . "\n";
                                  &redo_layout();
                                 };

##</code><code>##

$root->bind('<Configure>', sub {
                                  my $w = shift;
                                  print $w->Width . " and " . $w->Height . "\n";
                                  &redo_layout();
                                 };