You can define the classifier of a state using the Classifier list in the state property sheet. This allows you to link the state to a use case, a component or a class.
At the diagram level, you can also specify the context element of a state by filling in the Default Classifier list in the statechart diagram property sheet. As a result, each state that is created in a diagram using the State tool is automatically associated with the default classifier specified in the statechart diagram property sheet.
By default new diagrams are created with an empty value in the Default Classifier list, except sub-statechart diagrams that automatically share the same Classifier value defined on the parent decomposed state. The Default Classifier value is an optional value in the statechart diagram.
For general information about diagram properties, see "Diagram properties" in the Diagrams and Symbols chapter of the Core Features Guide.