The gift attribute may have been cached on the page. If the attribute does not show in the donation form part editor, this indicates the attribute has been deleted or marked inactive in Raiser's Edge. When we save the donation form part, this will update the page and override any possibly cached information which would remove the no longer active/existing attribute. 

If you would like the attribute to display on the page, you may need to add the gift attribute or update the attribute's settings in Raiser's Edge.