my $w = 250;
    my $h = 200;
    # Top-Level Fenster erzeugen
    my $tl_window = $Config{main_window}
        ->Toplevel(-title  => 'Über Kontoauszüge',
                   -width  => $w,
                   -height => $h
                   );
    my ($width,$height,$pos_x,$pos_y) = split /\+|x/,$Config{main_window}->geometry();
    
    # Top Level in Mitte des MainWindows positionieren
    $tl_window->geometry('+' .
                         int ($width / 2 + $pos_x - $w / 2) .
                         '+' .
                         int ($height / 2 + $pos_y - $h / 2)
                         );