Edit in JSFiddle

var app = angular.module('myApp', []);

app.controller('MainCtrl', function($scope) {
    $scope.selectAction = function() {

   };
   $scope.items = [
     { id: 1, g:'a', name: 'foo' },
     { id: 2, g:'a', name: 'bar' },
     { id: 3, g:'a', name: 'blah' },
     { id: 1, g:'b', name: 'foo' },
     { id: 2, g:'b', name: 'bar' },
     { id: 3, g:'b', name: 'blah' }
   ];
});

app.directive(
    'selectLatest', 
    function() {
        function fixSelectedIndex(elem){
            console.log('fix');
            console.log(elem[0]);
            var selectedText = 
                !!elem[0].selectedOptions
                    ? elem[0].selectedOptions[0].text
                    : elem[0].options[elem[0].selectedIndex].text,
                optionsLength = elem[0].options.length,
                i = 0,
                candidate;
            for(i=0; i<optionsLength;i++){
                candidate = elem[0].options[i].text;
                console.log('candidate: ' + candidate);
                if(selectedText === candidate){
                    elem[0].selectedIndex = i;
                    return;
                }
            }
        }
        
        return {
            // restrict to an attribute type.
            restrict: 'A',
            
            // element must have ng-model attribute.
            require: 'ngModel',
            
            // scope = the parent scope
            // elem = the element the directive is on
            // attr = a dictionary of attributes on the element
            // ctrl = the controller for ngModel.
            link: function(scope, elem, attr, ctrl) {
                console.log('link');
                elem.bind(
                    'blur', 
                    function(){fixSelectedIndex(elem);}
                );
                elem.bind(
                    'click', 
                    function(){fixSelectedIndex(elem);}
                );
            }
        };
    }
);

<h1>Same same, but different</h1>
<p>Selected index of duplicated items in form select elements</p>
<h2>Repro</h2>
<p>select a value from the first option group. Double check the selection is in the first option group:</p>
<div ng-app="myApp">
<div ng-controller="MainCtrl">
    <label for="select1">Without fix</label>
    <br/>
    <select
       id="select1"
       ng-model="selectedItem2" 
       ng-change="selectAction()"  
       ng-options="item.id as item.name group by item.g for item in items">
    </select>
    <br/>
   <label for="select2">With fix:</label>
    <br/>
    <select
       id="select2"
       ng-model="selectedItem1" 
       ng-change="selectAction()"
       select-latest="true"
       ng-options="item.id as item.name group by item.g for item in items">
    </select>
</div>
</div>