A Concurrent Region is an “orthogonal conjunctive” component of a composite state, allowing concurrency to be constructed.
A concurrent region is represented on the diagram by a tile of a composite state, separated from other regions by a dashed line.
ArgoUML currently only supports a horizontal division of a concurrent composite state in regions.
The description of the details panels of a concurrent region is identical to that of a composite state (see Section 20.4, “ Composite State ” and so is not duplicated here.