External References
When investigating dependencies in an assembly, features may exist that were created in the context of another assembly. Therefore, these external dependencies point to a component in another assembly.
In the case when the other assembly is in session, the corresponding parent (or child) component has a name of the assembly next to it in parentheses, for example, PARENT.PRT (OTHERASM). Setting such an object as current replaces the current assembly tree with a filtered tree of OTHERASM.ASM. You can investigate other dependencies in the context of this assembly. When you select a previous item from the first assembly tree, you restore the tree of your initial assembly.
In the case when the other assembly is not in session, the system cannot determine which component inside this other assembly participates in an external dependency. It can only show the other assembly as the context of the dependency. You then see the following parent OTHERASM.ASM (you cannot show a child from another assembly that is not in session). If you select this parent and try to set it as current, the system tells you that you should retrieve the assembly first. If you confirm this, the Reference Viewer dialog box automatically retrieves it and shows its tree. The system behaves then as described above for an assembly that is in session.