Form is not hidding after submit

Hi there,
I have a problem with a form. It looks really simple – the title is a question “Will you come?” and two options – yes or not. So, I’m choosing “yes” and I’ve receive a message that form was submitted successfully. After refreshing a page the form is still visible with answer (if I choose any options I get a error and it’s okay), but in options the value “hide after successfull submit” is checked. Could you tell me please what I have to do to hide that?

Thank you in advance.