2. (For advanced users only)

In the advanced section of forms, there are now options to set required URL parameters and a message to display (instead of the form) if the form is submitted without those required parameters.  Here's the use case:

When a form has "Update Record" turned on you can use the same form to edit a record or create a new record.  If the URL parameter "recid" exists, then the form assumes you are editing a record, if it does not, then it assumes you are creating a record.  In some cases, you want to only allow edits, hence, you want to be able to say if the recid URL parameter does not exist, then do not display the form and instead show a custom message.

A very common use case is when you use a URL parameter(s) to pass a value to a hidden field(s).  In some cases, that field cannot be empty because the value is required to edit or create the record.