Tkx::font_configure(
   "TkCaptionFont", -family => "Courier", 
                    -size => 15, 
                    -weight => "normal"
);
$top = Tkx::widget->new(q{.});
Tkx::tk___messageBox(
                  -parent  => $top,
                  -title   => 'Fehler',
                  -type    => 'ok',
                  -icon    => 'error',
                  -message => 'Diese Eingabe ist falsch'
               );