Tracker issues can contain reference fields, which are lookup and selection fields. Reference fields are variants of choice fields, but contain dynamic, externally controlled references to fields in other trackers, instead of selections from a static set of local choice options.

Reference fields can be useful when release numbers, for example, are stored in one tracker, and other trackers in different projects must refer to the list of release numbers.

If trackers need to be linked, such as a requirement tracker with a test tracker, reference fields can be used for a test tracker's references back to the list of requirements, to select the requirements that are relevant for the test.

Define reference fields using Tracker > Configure > Fields.

By clicking the link in the Layout and Content of a Choice you can show or define the reference field configuration, for example, for the Release field in most trackers.

You can configure multiple values selection for reference fields on the Field Properties tab. Multiple checkboxes automatically appear in the field properties for the field, after you define it as a reference field. You can define default values and access permissions for reference fields per status using the Field Access dialog box.

Reference fields can refer to the following types of objects:

A reference field can also refer to objects from multiple sources. For example, the change request subject refers to use cases or requirements: