Cannot assign custom field to a specific form

One of the custom fields I created continues to revert to "all forms" when I try to assign it to a specific form. I'm using Joomla! 3.1.1 with Payment Form version 3.0. Other custom fields can be assigned to specific forms.

Thanks in advance for any help!

Hi

That's strange. Could I please have admin account of your site so that I can check it myself ?

Tuan

Hi Tuan, I realize that this is a core field, and perhaps that is why it can't be assigned to specific forms? Thanks for your response, as always!

Ah Yes. That's the reason !

Tuan