anchor.diff:                labelCancel        : labelCancel,
                 axis               : pdc.axis,
                 values             : position.values,
  -              onValuesSelected   : function(selectedValues) {
  -                if (isAlreadyInClassification({ values: selectedValues }, classifications[startIndex]))
  +              onValuesSelected   : function(positions) {
  +                if (isAlreadyInClassification(positions[0], classifications[startIndex]))
                     alert("<fmt:message key='pdcPeas.positionAlreadyExist' bundle='${pdcBundle}'/>");
                   else
  -                  updatePositionInClassifications($elt, position, selectedValues, startIndex, endIndex);
  +                  updatePositionInClassifications($elt, position, positions[0].values, startIndex, endIndex);
                 }
               });
             }
  
positive.code:               labelOk            : labelOk,
                labelCancel        : labelCancel,
                axis               : pdc.axis,
                onValuesSelected   : function(selectedValues) {
                  var position = { values: selectedValues };
                  if (isAlreadyInClassification(position, classifications[startIndex]))
                    alert("<fmt:message key='pdcPeas.positionAlreadyExist' bundle='${pdcBundle}'/>");
                  else
                    addPositionInClassifications($elt, position, startIndex, endIndex);
                }
              });
            },
  
negative.code:        * classification at this index.
         * Once the position updated, the classification rendered within the HTML element $elt is refreshed.
         */
        function updatePositionInClassifications($elt, position, newValues, startIndex, endIndex) {
          var location = findPosition(position.values, classifications[startIndex].positions);
          updatePosition(classifications[startIndex].uri, {
            uri: location.position.uri,
            id: location.position.id,
            values: newValues},
          function(classification) {
            classifications[startIndex] = classification;
            setModified();
            if (endIndex > startIndex) {
              updatePositionInClassifications($elt, position, newValues, startIndex + 1, endIndex);
            } else {
              $elt.pdcPositions('refresh', classifications[startIndex].positions);
            }
  