In UML models, you can create composite structure diagrams to describe
the interaction between the internal parts, ports, and connectors of a structured
classifier.
You must be in the Modeling perspective and have a structure or freeform
diagram open that contains a structured classifier.
To create a composite structure diagram, in the diagram editor, right-click
a structured classifier; then click .
The containing classifier name appears in the heading label and any
previously defined elements are displayed in the frame.
Tip: You can also create a composite structure diagram
in the structure compartment of a classifier.