Wijmo 5[Flex Grid]

Check box in column header without using itemformatter

HTML

<link rel="stylesheet" href="http://cdn.wijmo.com/5.latest/styles/wijmo.min.css">
<script src="http://cdn.wijmo.com/5.latest/controls/wijmo.min.js"></script>
<script src="http://cdn.wijmo.com/5.latest/controls/wijmo.grid.min.js"></script>
<script src="http://cdn.wijmo.com/5.latest/interop/angular/wijmo.angular.min.js"></script>
 <div ng-app="app" ng-controller="appCtrl">
        <wj-flex-grid items-source="data" allow-sorting="false" control="flex" updated-view="updatedView(s,e)" >
            <wj-flex-grid-column header="Customer Id" binding="id"></wj-flex-grid-column>
            <wj-flex-grid-column header="Country" binding="country"></wj-flex-grid-column>
            <wj-flex-grid-column header="Date" binding="date"></wj-flex-grid-column>
            <wj-flex-grid-column header="Amount" binding="amount"></wj-flex-grid-column>
            <wj-flex-grid-column header="Active" binding="active">
                <wj-flex-grid-cell-template cell-type="ColumnHeader">Active <input type="checkbox" ng-model="chkBox" ng-change="isChanged()"/>
                </wj-flex-grid-cell-template>
            </wj-flex-grid-column>
        </wj-flex-grid>
       
    </div>

JavaScript

var countries = 'US,Germany,UK,Japan,Italy,Greece'.split(','),
       data = [];
        for (var i = 0; i < 10; i++) {
            data.push({
                id: i,
                country: countries[i % countries.length],
                date: new Date(2014, i % 12, i % 28),
                amount: Math.random() * 10000,
                active: i % 4 == 0
            });
        }
        var app = angular.module('app', ['wj']);
        app.controller('appCtrl', function ($scope) {
            $scope.data = new wijmo.collections.CollectionView(data);
            $scope.chkBox = true;
            $scope.isChanged = function () {
                var flex = $scope.flex;
             
                $scope.chkBox = !$scope.chkBox;
                console.log($scope.chkBox);
                cell = getGridCell(flex, 0, 4);                         
                // Click on header and update other cell
                var cb = cell.lastChild;
                cb.checked = $scope.chkBox;
                flex.beginUpdate();
                for (var i = 0; i < flex.rows.length; i++) {
                    flex.setCellData(i, 4, cb.checked);
                }
                flex.endUpdate();
                flex.refresh();
            };
           
            $scope.updatedView = function (s, e) {
                checkBoxChanged(s);
            };
            function checkBoxChanged(s) {             
                var flex = s;
                var cnt = 0;
                for (var i = 0; i < flex.rows.length; i++) {
                    if (flex.getCellData(i, 4) == true) {
                        cnt++;
                    }
                }
                var cell = getGridCell(flex, 0, 4);
                var cb = cell.lastChild;
                cb.checked = cnt > 0;                        
                cb.indeterminate = cnt > 0 && cnt < flex.rows.length;
              
            };
            //find html for column header
            function...