@Override
          public IterationMode next(final NodeType node) {
            toSelect.addAll(GraphAlgorithms.collectChildren(node, deselectedFilter));

            return IterationMode.CONTINUE;
          }
Expands the current selection down. This means that all children of the currently selected
nodes are selected too.

@param <NodeType> The node type of all nodes in the graph.
@param graph The graph where the current selection is expanded.
java/zylib/src/main/java/com/google/security/zynamics/zylib/gui/zygraph/helpers/GraphHelpers.java