Dear Elders, this dialog misbehaves, does not listen to me, what should I do?

Read Coping with Scoping, How do I post a question effectively?, and start posting code that compiles, code like

#!/usr/bin/perl --
use Tk;
use Tk::Dialog;
my $mw = tkinit;
my $snot = "snot";
$mw->Label( -textvariable => \$snot )->pack;;
$mw->Button(
   -text => 'wipe',
   -command => sub {
        my $d = $mw->Dialog(
            -title => "Title",
            -text => "Text",
            -buttons => [ "OK", "Cancel" ] 
        );
    $d->geometry('200x200+40+40');
    $snot .= '('.  $d->Show . ")\n";
    $d->destroy();
    undef $d;
},
)->pack;
MainLoop;
__END__
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