Tooltip on hover not nearest points

Show tool tip on point hover not nearest point

HTML

<script src="http://code.highcharts.com/stock/highstock.js"></script>
 
<div id="container" style="min-width: 500px"></div>

JavaScript

$(function() {
     var chart, yAxis = [], seriesOptions = [], seriesCnt=0, top =0, yAxisCnt=0,
                topPadding = 10,
                visibleSeriesMap = new Object();
                
                visibleSeriesMap['count']  =  true;
                visibleSeriesMap['line']  =  true;
                visibleSeriesMap['line0']  =  true;
                visibleSeriesMap['dataLabel']  =  true;

                
                function getSeriesGroup(name, length, visible) {
                    var seriesIdArray = [];
                    for(var i=0;i < length;i++){
                        seriesIdArray.push(name.toLowerCase() + i);
                    }
                    var series = {
                        id  : name.toLowerCase(),
                        name: name,
                        connectedSeries: seriesIdArray,
                        color: '#000000',
                        selected:visible,
                        visible:visible
                    };
                    return series;    
                }
                           
                var data1 = [{
                        name: 'RBC Count',
                        y: 75,
                        x: 1333391400000
                    }, {
                        name: 'RBC Count',
                        y: 90,
                        x: 1336933800000
                    }, {
                        name: 'RBC Count',
                        y: 120,
                        x: 1337193000000
                    }, {
                        name: 'RBC Count',
                        y: 80,
                        x: 1338921000000
                    }, {
                        name: 'RBC Count',
                        y: 85,
                        x: 1341772200000
                    }, {
                        name: 'RBC Count',
                        y: 95,
                        x: 1343068200000
                    }],
                line = [{
                   ...