title: Extjs 6 viewModel and Store
body: <p>I am using Extjs 6 to build grid view.
  this is my Store :
  schedule.js</p>
  
  <pre><code>Ext.define('schedulewise.store.schedule.Schedule', {
      extend: 'Ext.data.Store',
      alias: 'store.Schedule',
      requires: [
          'schedulewise.utils.Config'
      ],
      model: 'schedulewise.model.schedule.Schedule',
      autoLoad: true,
      proxy: {
          type: 'rest',
          url: 'http://127.0.0.1:8080/' + schedulewise.utils.Config.projectName + '/rest/cserver/dto/schedule/allInfo?request=loadSchedule',
      useDefaultXhrHeader: false,
          reader: {
              type: 'json'
          },
          writer: {
              type: 'json'
          }
  }
  </code></pre>
  
  <p>this is my viewModel:ScheduleModel.js</p>
  
  <pre><code>Ext.define('schedulewise.view.schedule.ScheduleModel', {
      extend: 'Ext.app.ViewModel',
      alias: 'viewmodel.ScheduleModel',
      stores: {
          Schedule: {
              type:'Schedule'
          }
      },
      data:{
          title:'Schedules'
      }
  });
  </code></pre>
  
  <p>this is my view:</p>
  
  <pre><code>Ext.define("schedulewise.view.schedule.MainPanel", {
      extend: 'Ext.grid.Panel',
      xtype: 'MainPanel',
      requires: [
          'schedulewise.utils.Config'
      ],
      layout: 'fit',
      region: 'center',
      controller: 'ScheduleController',
      viewModel: 'ScheduleModel',
      bind: {
          store: '{Schedule}',
          title:'{title}'
      },
      columns: [
          {
              text: 'Name',
              dataIndex: 'scheduleName',
              resizable: false,
              hideable: false,
              sortable: false,
              flex: 25 / 100
          },
          {
              text: 'lastestVersion',
              dataIndex: 'lastestVersion',
              resizable: false,
              hideable: false,
              sortable: false,
              flex: 25 / 100
          },
          {
              text: 'currentVersion',
              dataIndex: 'lastestVersion',
              resizable: false,
              hideable: false,
              sortable: false,
              flex: 25 / 100
          },
          {
              text: 'date range',
              dataIndex: 'scheduleRange',
              resizable: false,
              hideable: false,
              sortable: false,
              flex: 25 / 100
          }
      ]
  });
  </code></pre>
  
  <p>i found that when the view loaded,Store always requests two times.
  I do not know why?
  <a href="http://i.stack.imgur.com/BCWmr.png" rel="nofollow">screenshot</a></p>