strange change of grid due to double click

[lightyear416]

Hi,everyone.There is a odd event I meet with.When I double click the stripe of content of grid,the stripe will go forward a little.I don't konw the reason that leading to this.Can somebody help me to modify.
the org grid:

after double click:

grid columns:

        columns: [
            { id: 'objectnum', text: '监测对象编号', dataIndex: 'ObjectNum', sortable: false, hidden: true, width: 100 },
             { id: 'objectname', text: '监测对象名字', dataIndex: 'ObjectName', sortable: false, hidden: false, flex: 1 },
            { id: 'monitortypeid', text: '监测类型编号', dataIndex: 'MonitorTypeID', sortable: false, hidden: true, width: 100 },
            { id: 'monitortypename', text: '所属监测类型', dataIndex: 'MonitorTypeName', sortable: false, hidden: false, flex: 1 },
            { id: 'areaid', text: '项目区域ID', dataIndex: 'AreaID', sortable: false, hidden: true, width:100 },
            { id: 'areaname', text: '所属项目区域', dataIndex: 'AreaName', sortable: false, hidden: false, flex: 1 },
            {id: 'objectdescription', text: '监测对象描述', dataIndex: 'ObjectDescription', sortable: false, hidden: false, flex: 1 }
        ]

the event I fire is 'itemdblclick': function (view, record, item, index) {} .However I have not oprate grid for any code.

[mitchellsimoens]

Inspect the DOM to see if there is some CSS. I do not have this in an example grid.