Shows how to use EReferenceItemProvider to create tree nodes (folders) for EReferences

ereference-item-provider.java

	@Override
	public Collection<?> getChildren(Object object) {
		List<EReferenceItemProvider> children = eReferenceItemProviders.get(object);
		if (children == null) {
			children = new ArrayList<>();
			eReferenceItemProviders.put(object, children);
			children.add(new EReferenceItemProvider(this, (EObject) object, AppPackage.Literals.CONTAINER__ELEMENTS));
			children.add(new EReferenceItemProvider(this, (EObject) object, AppPackage.Literals.ABSTRACT_ACTION__ACTION_MAPPINGS)); 
			children.add(new EReferenceItemProvider(this, (EObject) object, AppPackage.Literals.ACTION_BASE__CONTENT)); 
		}
		return children;
	}