captcha field size 1

Hi
I just installed the Really Simple Captcha and upgraded to the following versions:
Wordpress 3.6
Contact Form 7: 3.5.2
Really simple capycha : 1.7

The problem is that the form input is only of size 1. A bit small. The entire HTML stuff:

<p>Controle Code<br />
  <input type="hidden" name="_wpcf7_captcha_challenge_captcha-218" value="350595419" /><img class="wpcf7-form-control wpcf7-captchac wpcf7-captcha-captcha-218" width="72" height="24" alt="captcha" src="http://lokaleveerkracht.nl/wp-content/uploads/wpcf7_captcha/350595419.png" /> <br><br />
  <span class="wpcf7-form-control-wrap captcha-218"><input type="text" name="captcha-218" value="" size="1" class="wpcf7-form-control wpcf7-captchar" /></span>  </p>
<p><input type="submit" value="Verzenden" class="wpcf7-form-control wpcf7-submit" /></p>

If you have the same problem, do like me. Edit the code yourself.
Using the plugin editor, contact form 7, contact-form-7/modules/captcha.php

Out-comment the line where the attribute size is set wrong:

// $atts['size'] = $tag->get_size_option( '40' );

and hardcode to, say, 6.

$atts['size'] = 6;

Good luck!