64.000 Captchas

Hello,

my new blog is not yet online but already has over 64.000 Captcha files in the “wpcf7_captcha” folder? Why? Why is this captcha file not every time deleted when not used? With every page load another file is created. That is pretty senseless :-))

The folder has 777 rights, so what is wrong here?

http://ww.wp.xz.cn/extend/plugins/contact-form-7/