hey everyone, I just started to learn about Sencha Ext JS 4 especially the Charting classes and recently I've come to a big issue:

I've generated a line chart and tried to apply tool tips on every point of the chart. The problem is that the hovering area of each point is way too large and when I try to hover a point which is very close to another point, the chart selects both of them. I'd like to somehow reduce this hovering area if possible, and I tried to look for a property in the Sencha Ext JS 4 documentation but I didn't find anything useful.

Code:
                    
var seriesArray = new Array();
 for (i = 0; i < dataArray.length; i++) {

 seriesArray.push({
        type: 'line',
         highlight: {
         size: 7,
         radius: 7
             },
                     axis: 'left',
                     xField: 'name',
                     yField: dataArray[i],
                     markerConfig: {
                     type: 'circle',
                     size: 4,
                     radius: 3,
                     'stroke-width': 0
                  },
               tips: {
                trackMouse: true,
                width: 140,
                height: 28,
               renderer: function (storeItem, item) {


              this.setTitle(storeItem.get('name') + ': ' + storeItem.get(item.series.yField) + ' views');

                   }
              }
       });
 }

        Ext.create('Ext.chart.Chart', {
         renderTo: document.getElementById("div0"),
          width: 500,
          height: 300,
          animate: true,
          store: store3,
          axes: [
        {
            type: 'Numeric',
            position: 'left',
            //maximum: 50,
            fields: dataArray,
            label: {
                renderer: Ext.util.Format.numberRenderer('0,0')
            },
            title: 'Sample Values',
            grid: true,
            minimum: 0
        },
        {
            type: 'Category',
            position: 'bottom',
            fields: ['name'],
            title: 'Sample Metrics'
        }
    ],
        series: seriesArray
 });


                }
            });
The code above is for defining an array of series for the chart and then generating the chart itself. Maybe I need to add a new property to the line chart or to each series I'm adding..

Please help me someone,, Thank you very much !!!!