code: @Override
      protected void handleIncompleteEntityProblem(WstxInputSource closing)
          throws XMLStreamException
      {
          // Did it start outside of declaration?
          if (closing.getScopeId() == 0) { // yup
              // and being WFC, need not be validating
              _reportWFCViolation(entityDesc(closing) + ": "
                            +"Incomplete PE: has to fully contain a declaration (as per xml 1.0.3, section 2.8, WFC 'PE Between Declarations')");
          } else {
              // whereas the other one is only sent in validating mode..
              if (mCfgFullyValidating) {
                  _reportVCViolation(entityDesc(closing) + ": "
                                +"Incomplete PE: has to be fully contained in a declaration (as per xml 1.0.3, section 2.8, VC 'Proper Declaration/PE Nesting')");
              }
          }
      }
docs: Handling of PE matching problems is actually intricate; one type
  will be a WFC ("PE Between Declarations", which refers to PEs that
  start from outside declarations), and another just a VC
  ("Proper Declaration/PE Nesting", when PE is contained within
  declaration)