Very nice. I needed some bigger fonts though, especially for fullscreen use, and I added this to your code. It works well on linux. I just tucked the code in between the new MainWindow and geometry lines.

$w{mw} = MainWindow->new;

################  aded for font control ############3
use Tk::FontDialog;

my $fd = $w{mw}->FontDialog(-nicefont => 0,
               -title => 'Select Font',
               -applycmd => \&apply_font,
               -familylabel => 'Schrift~familie',
               -fixedfontsbutton => 1,
               -nicefontsbutton => 1,
              );


my $b = $w{mw}->Button(-text => 'Choose Font',
                  -bg => 'lightyellow',
                  -command => sub {
                     my $font = $fd->Show;
                      apply_font($font);
                  })->pack;

sub apply_font {
    my $font = shift;
    if (defined $font) {
        $b->configure(-font => $font);
        $w{mw}->RefontTree(-font => $font, -canvas => 1);
    }
}
############### end of font control ######################

$w{mw}->geometry('600x480');
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