Denying default value in dropdown list

Hello, 1st of all thanks for this very needed plugin!

I’m just experimenting with the Relationship field, but I can’t get a dropdown list where the default value is rejected (false) because of the field being marked as required.

If I put all of my value|label rows in the custom options textarea, one per line as stated in the help, the resulting list defaults to the 1st row, with no “–Select one–” default option appearing; so the dropdown list is always true.

If I put something like:
(nothing here)|(nothing here) as the 1st row, the value showed in the resulting list is empty but the list is still true.

So what’s the proper way to put a default value which cannot pass as true when the required attribute is ckecked?

Thanks!