Bug 32664 Package Explorer: hierarchical layout and back-linking don't work allways together.
The following triggers it: - initially 'flat layout' is used, 'link with editor' is on or off - open a java file - use 'collapse all' in the package explorer - select 'hierarchical layout' - switch 'link with editor' on or off&on -> no back-linking
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerContentProvider.java
continue;
				}
				if (entry != null && entry.getEntryKind() == IClasspathEntry.CPE_CONTAINER) 
					containers.add(entry);
				else
					result.add(root);
			} else {
				result.add(roots[i]);
			}
		}
		for (Iterator each= containers.iterator(); each.hasNext();) {
			IClasspathEntry element= (IClasspathEntry) each.next();
			result.add(new ClassPathContainer(project, element));
		}		
		return result.toArray();
	}
	private Object[] getContainerPackageFragmentRoots(ClassPathContainer container) throws JavaModelException {
		return container.getPackageFragmentRoots();
	}
	private Object[] getNonJavaProjects(IJavaModel model) throws JavaModelException {
		return model.getNonJavaResources();
	}
	public Object getParent(Object child) {
		if (needsToDelegate(child)) {
			return fPackageFragmentProvider.getParent(child);
		} else
			return super.getParent(child);
	}
	/**
	 * Returns the given objects with the resources of the parent.