Canonical behavior occurs in specific elements in a UML model. You can disable the canonical mode for specific diagram element compartments, such as a state region and an activity partition. Canonical mode is always enabled for all list compartments and interaction diagrams.
When the canonical mode is turned off, changes that you make to the semantic
model are not reflected in the diagram. The ability to turn off canonical
behavior is useful if you import Rose models, which have no canonical reflection
of semantic content.