Personalization of a field at invoice header is not working properly.

Hi all,

 

I personalized the invoice workbench form to make the ‘Document Category Name’ field, at invoice header, as mandatory. This prompts a warning message at new record instance & displays the field in yellow color too. But system is allowing to save/validate the record without doing entry in the said field. Please guide.

 

Regards,

Abdul Rehman.