The scratchpad is volatile. Someone coming in later having a similar problem won't be able to benefit from the answers given here if you decided to remove the code from your scratchpad. For posterity, here's the code in question:

use warnings;
use strict;

use Tkx;

$Tkx::TRACE = 1;

our $VERSION = "1.0.0";

my ($mw, $tw);

$mw = Tkx::widget->new(".");
$mw->configure(-menu => mk_menu($mw));
Tkx::wm_title($mw, "GutThing-$VERSION");

my ($height, $width, $wrap) = (20, 80, "none");
$tw = $mw->new_text(
    -height => $height,
    -width => $width,
    -wrap => $wrap,
);

$tw->g_pack(
    -anchor => "center",
    -expand => 1, 
    -fill => "both",
);

$tw->g_focus;

$tw->insert("end", "If you can read this it worked");
$tw->insert("end", " but I don't do much at the moment.");
$tw->insert("end", " This is a long line that doesn't wrap.");
$tw->insert("end", " We don't wrap our lines in this editor for PPing.
+\n");
$tw->insert("end", "If you type here the line should scroll if you go 
+longer than window width.\n");

Tkx::MainLoop();
exit;

sub mk_menu {
    my $mw = shift;
    my $menu = $mw->new_menu;

    my $file = $menu->new_menu(
        -tearoff => 0,
    );
    $menu->add_cascade(
        -label => "File",
        -underline => 0,
        -menu => $file,
    );
    return $menu;
}
[download]

Sorry that I can't help you, though.