You can collapse or expand compartments for the different members of class, interface, namespace, enum, and structure (C++ projects only) elements. By default, the compartments for these elements are displayed on the diagram as a straight line. You can use the Options dialog window to set viewing preferences for compartment controls. Adding compartment controls is particularly useful when you have large container elements with content that does not need to be visible at all times.

1. Select the class (or interface) on the diagram.
2. Click the “+” or “-” in the left corner of the compartment.

1. Open the Options dialog box.
2. Select the Modeling(level)DiagramAppearanceNodes category.
3. In this category, edit the Show compartments as line field.