sencha pie charts iinteractions
===

i am working on sencha pie chart i need to add some interactions in this like rotation . i have added interactions config in my chart but it is not working . i am using ext-core.js ,ext-chart.js ,add a css file here is my code .
thanks in advance  

    Ext.onReady(function () {
        var chart = null;
        function refresh() {
            var series = chart.series.items,
                len = series.length;
    
            for (var i = 0; i < len; i++) {
                s = series[i];
                s.donut = 35;
            }
            chart.redraw();
        }
        store1.loadData(generateData(12));
        chart = new Ext.chart.Chart({
            width: 800,
            height: 600,
            animate: true,
            store: store1,
            renderTo: Ext.getBody(),
            legend: {
                position: 'right'
            },
    			interactions: [{
        type: 'pierotate'
    }],
            insetPadding: 25,
            theme: 'Base:gradients',
            series: [{
                type: 'pie',
                field: 'data1',
                showInLegend: true,
                tips: {
                	  trackMouse: true,
                	  width: 140,
                	  height: 28,
                	  renderer: function(storeItem, item) {
                	    this.setTitle(storeItem.get('name')+': '+storeItem.get('data1')+'$');
                	  }
                	},
                highlight: {
                  segment: {
                    margin: 20
                  }
                },
                label: {
                    field: 'name',
                    display: 'rotate',
                    contrast: true,
                    font: '18px "Lucida Grande", "Lucida Sans Unicode", Verdana, Arial, Helvetica, sans-serif'
                },
                animate: true
            }]
        });
        refresh();
        });