Hi again, I was looking at this offline, and thought it would be nice if your had a "fontselect" dialog. The "Tk::FontDialog" works on Linux and Win32. Here are some additions,(which you might consider). I have it working on my linux machine, and you might want to check how changing fonts may affect your "line-numbers display".

I didn't fully make the $font an object variable, you could do that. Anyways:

package main;
use Tk;
use Tk::ROText;
use Tk::DialogBox;
use Tk::FontDialog;
#use Data::Dumper; 
    
our $VERSION = 0.1;
        
# create the main window, a menu frame at top, a second scrollbar at r
+ight and a scrolled
my $app;
$app->{mw} = MainWindow->new( -title => "hugepad" );
$app->{menu} = $app->{mw}->Frame()->pack( -side     => "top",   -fill 
+=> "x" );
        
my $font;
my $fd = $app->{mw}->FontDialog(-nicefont => 0,
                       -title => 'Select Font',
                       -applycmd => \&apply_font,
                       );
    
$app->{fontbut} = $app->{menu}->Button(-text => 'Choose Font',
          -command => sub {
                $font = $fd->Show;
                  apply_font($font);
            })->pack(-side => 'right');
[download]

and

sub apply_font {
    my $font = shift;
    if (defined $font) {
        $app->{fontbut}->configure(-font => $font);
        $app->{mw}->RefontTree(-font => $font);
    }
}
[download]