系统BUG：平行坐标系中有多个'category'坐标轴时从第2个'category'轴无法选择区间echarts category配置项内容和展示

当把平行坐标系的示例中的日期轴修改为'category'类型后，“等级”轴出现无法选择区间的现象。试了一个多个'category'类型轴，只有第1个'category'轴可以选择，其它的无法选择区间。可能是系统的Bug

      //Begin:option ============================================            
// Schema:
// date,AQIindex,PM2.5,PM10,CO,NO2,SO2
var dataBJ = [
    ["周一",55,9,56,0.46,18,6,"良"],
    ["周二",25,11,21,0.65,34,9,"优"],
    ["周三",56,7,63,0.3,14,5,"良"],
    ["周四",33,7,29,0.33,16,6,"优"],
    ["周五",42,24,44,0.76,40,16,"优"],
    ["周六",82,58,90,1.77,68,33,"良"],
    ["周日",74,49,77,1.46,48,27,"良"]
];

var dataGZ = [
    ["周一",26,37,27,1.163,27,13,"优"],
    ["周二",85,62,71,1.195,60,8,"良"],
    ["周三",78,38,74,1.363,37,7,"良"],
    ["周四",21,21,36,0.634,40,9,"优"],
    ["周五",41,42,46,0.915,81,13,"优"],
    ["周六",56,52,69,1.067,92,16,"良"],
    ["周日",64,30,28,0.924,51,2,"良"]    
];

var dataSH = [
    ["周一",91,45,125,0.82,34,23,"良"],
    ["周二",65,27,78,0.86,45,29,"良"],
    ["周三",83,60,84,1.09,73,27,"良"],
    ["周四",109,81,121,1.28,68,51,"轻度污染"],
    ["周五",106,77,114,1.07,55,51,"轻度污染"],
    ["周六",109,81,121,1.28,68,51,"轻度污染"],
    ["周日",106,77,114,1.07,55,51,"轻度污染"]
];

var schema = [
    {name: 'date', index: 0, text: '日期'},
    {name: 'AQIindex', index: 1, text: 'AQI'},
    {name: 'PM25', index: 2, text: 'PM2.5'},
    {name: 'PM10', index: 3, text: 'PM10'},
    {name: 'CO', index: 4, text: ' CO'},
    {name: 'NO2', index: 5, text: 'NO2'},
    {name: 'SO2', index: 6, text: 'SO2'},
    {name: '等级', index: 7, text: '等级'}
];

var lineStyle = {
    normal: {
        width: 1,
        opacity: 0.5
    }
};

option = {
    backgroundColor: '#333',
    legend: {
        bottom: 30,
        data: ['北京', '上海', '广州'],
        itemGap: 20,
        textStyle: {
            color: '#fff',
            fontSize: 14
        }
    },
    tooltip: {
        padding: 10,
        backgroundColor: '#222',
        borderColor: '#777',
        borderWidth: 1,
        formatter: function (obj) {
            var value = obj[0].value;
            return '<div style="border-bottom: 1px solid rgba(255,255,255,.3); font-size: 18px;padding-bottom: 7px;margin-bottom: 7px">'
                + obj[0].seriesName + ' ' + value[0] + '日期：'
                + value[7]
                + '</div>'
                + schema[1].text + '：' + value[1] + '<br>'
                + schema[2].text + '：' + value[2] + '<br>'
                + schema[3].text + '：' + value[3] + '<br>'
                + schema[4].text + '：' + value[4] + '<br>'
                + schema[5].text + '：' + value[5] + '<br>'
                + schema[6].text + '：' + value[6] + '<br>';
        }
    },
     //dataZoom: {
      //   show: true,
       //  orient: 'vertical',
      //   parallelAxisIndex: [0]
    // },
    parallelAxis: [
        {dim: 0, name: schema[0].text, inverse: true,  type: 'category', nameLocation: 'start', data: ["周一","周二","周三","周四","周五","周六","周日"]},
        {dim: 1, name: schema[1].text},
        {dim: 2, name: schema[2].text},
        {dim: 3, name: schema[3].text},
        {dim: 4, name: schema[4].text},
        {dim: 5, name: schema[5].text},
        {dim: 6, name: schema[6].text},
        {dim: 7, name: schema[7].text,  type: 'category', data: ['优', '良', '轻度污染', '中度污染', '重度污染', '严重污染']}
    ],
    visualMap: {
        show: true,
        min: 0,
        max: 150,
        dimension: 2,
        inRange: {
            color: ['#d94e5d','#eac736','#50a3ba'].reverse(),
            // colorAlpha: [0, 1]
        }
    },
    parallel: {
        left: '10%',
        right: '18%',
        bottom: 80,
        parallelAxisDefault: {
            type: 'value',
            name: 'AQI指数',
            nameLocation: 'end',
            nameGap: 20,
            nameTextStyle: {
                color: '#fff',
                fontSize: 12
            },
            axisLine: {
                lineStyle: {
                    color: '#aaa'
                }
            },
            axisTick: {
                lineStyle: {
                    color: '#777'
                }
            },
            splitLine: {
                show: false
            },
            axisLabel: {
                textStyle: {
                    color: '#fff'
                }
            }
        }
    },
    series: [
        {
            name: '北京',
            type: 'parallel',
            lineStyle: lineStyle,
            data: dataBJ
        },
        {
            name: '上海',
            type: 'parallel',
            lineStyle: lineStyle,
            data: dataSH
        },
        {
            name: '广州',
            type: 'parallel',
            lineStyle: lineStyle,
            data: dataGZ
        }
    ]
};  
//End:option============================================