return 0;  if (((IJavaElement)e1).getParent() != ((IJavaElement)e2).getParent())
	public int compare(Viewer viewer, Object e1, Object e2) {		if (!(e1 instanceof ISourceReference))			return 0;		if (!(e2 instanceof ISourceReference))			return 0;				try {			ISourceRange sr1= ((ISourceReference)e1).getSourceRange();			ISourceRange sr2= ((ISourceReference)e2).getSourceRange();			if (sr1 == null || sr2 == null)				return 0;						return sr1.getOffset() - sr2.getOffset();					} catch (JavaModelException e) {			return 0;		}	}