Xref Annotation refers to the display of the cross reference values and these are made visible from the option - Setup - Settings - Display - Xref Annotation. To create the actual cross references you run either Tools - Update Other Objects - Cross Reference or Tools - Cross Reference. The differences between these two commands is that the first is easier to use but currently only works for flat designs, the second mechanism uses a utility called SCOUT that is more complex to set up but will work with hierarchy. We intend to enhance the first mechanism to do cross-referencing with hierarchical designs in a future release. If your designs are flat then the first option is the simplest to use.
Clik here to view.
