Standard field (DueByDate) removed from incident template
I have apparently accidentally deleted the DueByDate field. It does not appear in my default incident template, and it is not available in the list of fields that is displayed to the left of the template as I customize it. I can tell from e-mail that I receive that the variable is being set somehow, but I am not setting it. How is the $DueByDate variable being set if the requester doesn't set it, and how can I restore that field as an option?