Nest elements in one another in the diagram window
You can nest one model element in another in the diagram window if the UML specification allows for this. This section describes how to nest one class in another.
Procedure. Procedure
Drag a class to another class. An invisible edge of the Owning class type is created between the two classes. In the Explorer tree, the nested class is placed below the containing class.
If you move the containing class, the nested class is also moved automatically.
Click the nested class and drag it from the containing class to a free area of the diagram. The relationship is kept. In the Explorer tree, the nested class remains positioned below the superior class.
The model element has been nested and the nesting removed again.