ext中设置grid单选，取消选择

原代码（无法取消选择）如下：

selModel: Ext.create('Ext.selection.CheckboxModel', {

  mode: "SINGLE",

  allowDeselect: true,

  onHeaderClick: function (headerCt, header, e) {

  }

}),

修改后代码：

  selModel: {

                    selType: "checkboxmodel",

                    mode: 'SINGLE',

                    checkOnly: 'true',

                    allowDeselect: true,

                    onHeaderClick: function (headerCt, header, e) {

                    }

                },

完美解决问题

原文：http://stackoverflow.com/questions/39616345/sencha-extjs-grid-checkbox-model-single-mode-deselect