Contact form 7 error

Hi, I've removed the subject field as I don't need it on the page using the check box 'show subject field' on the upfront option sidebar.

When I try and send a message however, the form errors out with the message "You must write a subject for the message."

I can't see an option in the contact for 7 plugin to remove the subject form which doesn't actually exist in the back end.

Please advise.

Thank you