Product: SharePoint 2010
A person or group must be included within the security group of a site in order for that specific person or group to be available within the column drop down within a Datasheet View. Follow the below steps if the drop down does not show the proper people or group selections.
– navigate to the site
– select Site Actions > Site Settings > People and Groups
– select the appropriate security group (owner, member, visitor, etc.)
– add each person and group to the site
Refresh the Datasheet View and the drop down selections will now include the additional people and groups.