if (fParentPosition == null) throw new BadLocationException();
return fParentPosition != null;
	private void enforceNestability(LinkedPositionGroup group) throws BadLocationException {		// TODO debug trace the erroneous nestings.		Assert.isTrue(fParentEnvironment == null || fParentEnvironment.fGroups.size() > 0);		if (fParentEnvironment == null)			return;		for (Iterator it= fParentEnvironment.fGroups.iterator(); it.hasNext(); ) {			LinkedPositionGroup pg= (LinkedPositionGroup) it.next();			LinkedPosition pos= pg.adopt(group);			if (pos != null && fParentPosition != null && fParentPosition != pos)				throw new BadLocationException();			else if (fParentPosition == null && pos != null)				fParentPosition= pos;		}		// group must fit in exactly one of the parent's positions		if (fParentPosition == null)			throw new BadLocationException();	}