  We show that the groupoids of two directed graphs are isomorphic if and only
if the two graphs are orbit equivalent by an orbit equivalence that preserves
isolated eventually periodic points. We also give a complete description of the
(topological) isolated points of the boundary path space of a graph. As a
result, we are able to show that the groupoids of two directed graphs with
finitely many vertices and no sinks are isomorphic if and only if the two
graphs are orbit equivalent, and that the groupoids of the stabilisations of
two such graphs are isomorphic if and only if the stabilisations of the graphs
are orbit equivalent.
