If you create a virtual table or subtable from a real table (called the "main" table for the purposes of this discussion), the new table has the same fields as the main table at the time the new table was created. If you later add fields to the main table (for example, fields were added to the table and you refreshed the data dictionary or you added calculated fields) or change the properties of fields in the main table (such as data type or size), the virtual or subtable isn't updated.
To make a virtual or subtable match the fields in the main table, select the virtual or subtable in the data dictionary, then choose Update Virtual/Subtable to Match Main Table from the Objects menu. Alternatively, you can right-click the virtual or subtable and choose Update Virtual/Subtable to Match Main Table from the shortcut menu. You are prompted whether you want to update the Caption, Heading, and Comments properties. If you chose Yes, those properties are updated. If you chose No, they are left alone and other only other properties such as Data Type and Format are updated.