docs: public ContentMatcher remove(Conjunction selector, MatchTarget object, InternTable subExpr, OrdinalPosition parentId)
      throws MatchingException
    {
      if (tc.isEntryEnabled())
  	    tc.entry(this,cclass, "remove","selector: "+selector+", object: "+object);
  
      vacantChild = vacantChild.remove(selector, object, subExpr, ordinalPosition);
      ContentMatcher result = this;
      if (vacantChild == null)
        result = null;
  
      if (tc.isEntryEnabled())
  	    tc.exit(this,cclass, "remove","result: " + result);
  
      return result;
    }