The most common reason why the form headline or an HTML block freezes and can’t be edited at all (sometimes triggering even other Form Editor problems) is the fact that the content that is copy/pasted into that field includes something else than text and HTML tags (which are the supported types of input).
For example, we had one situation when the user pasted XML code from a Word file into the form headline and couldn’t make any further edits to it.
If you are in a similar situation, contact us
and we will clear up the form field for you. Keep in mind that only text and HTML code can be used in form headlines and HTML block