private void populate(CollectorGem collectorGem, Map<CollectorGem, Set<CollectorGem>> targetToCollectorMap) {
// Create a node for the collector, and add it to the parent.
CollectorNode collectorNode = getCollectorNode(collectorGem);
((ArgumentTreeNode)getRoot()).add(collectorNode);
collectorNode.removeAllChildren();
// Add node for the arguments.
List<Gem.PartInput> reflectedInputs = collectorGem.getReflectedInputs();
for (final Gem.PartInput reflectedInput : reflectedInputs) {
ArgumentNode reflectedInputNode = getArgumentNode(reflectedInput);