When a label connected to a database file is open in design view, the database preview is not showing. Instead BarTender shows database field names or place holder information.
Bartender 2016 and later
Professional Edition and higher
BarTender will attempt to show database previews whenever you connect to a database. However, this may turn off due problems connecting/retrieving previews for certain database types. To enable the database previews, click the Connect/Disconnect icon in the lower left portion of the template.