code: @Override
  	protected String getURIFragmentRootSegment(EObject eObject) {
  		if (unloadingContents == null) {
  			IParseResult parseResult = getParseResult();
  			if (parseResult != null && eObject == parseResult.getRootASTElement()) {
  				return "0"; 
  			}
  		}
  		return super.getURIFragmentRootSegment(eObject);
  	}
docs: {@inheritDoc}
  <p>
  Overridden to make sure that we do not initialize a resource
  just to compute the root URI fragment for the parse result.