updateNamespaceIndex(contribution, true);
	synchronized void addContribution(Contribution contribution) {		isDirty = true;		Object Id = contribution.getKey();		KeyedElement existingContribution = getFormerContributions().getByKey(Id);		if (existingContribution != null) { // move it from former to new contributions			removeContribution(Id);			newContributions.add(existingContribution);		} else			existingContribution = newContributions.getByKey(Id);		if (existingContribution != null) // merge			((Contribution) existingContribution).mergeContribution(contribution);		else			newContributions.add(contribution);	}