If the Transition explicitly enters one or more Regions (in case of a fork), these Regions are entered explicitly and the others by default. Source Unified Modeling Language 2.5.1
If the Transition terminates on the edge of the composite State (i.e., without entering the State), then all the Regions are entered using the default entry rule above. Source Unified Modeling Language 2.5.1
If the composite State is also an orthogonal State with multiple Regions, each of its Regions is also entered, either by default or explicitly. Source Unified Modeling Language 2.5.1
When exiting from an orthogonal State, each of its Regions is exited. After that, the exit Behavior of the State is executed. Source Unified Modeling Language 2.5.1
State configurations Gallery Tutorial TRAIL: Webel's ultimate guide to Systems Modeling Language (v1) with MagicDraw/Cameo Section 01:03: UML Behavior: StateMachines quick start Slide kind UML StateMachine Diagram
Kinds of States Gallery Tutorial TRAIL: Webel's ultimate guide to Systems Modeling Language (v1) with MagicDraw/Cameo Section 01:03: UML Behavior: StateMachines quick start Slide kind UML StateMachine Diagram
uml101 - StateMachines - NOTATION REFERENCE CARD Gallery Tutorial TRAIL: Webel's ultimate guide to Systems Modeling Language (v1) with MagicDraw/Cameo Section 01:03: UML Behavior: StateMachines quick start Slide kind UML StateMachine Diagram
fork – fork Pseudostates serve to split an incoming Transition into two or more Transitions terminating on Vertices in orthogonal Regions of a composite State. Source Unified Modeling Language 2.5.1
