title: ExtJS Grid renders Empty Cells
body: <p><img src="https://i.stack.imgur.com/9Y5h9.png" alt="http://i.imgur.com/swGAk2D.png"></p>
  
  <h2>Model</h2>
  
  <pre><code>Ext.define('XXX.User', {
      extend: 'Ext.data.Model',
      fields: [
          'name',
          'email',
          'nick',
          'mobile',
          { name: 'create_time', type: 'date', dateFormat: 'Y-m-d H:i:s' }
      ]
  }); 
  </code></pre>
  
  <h2>Ajax Response</h2>
  
  <pre><code>{
      "error": "",
      "errno": 0,
      "success": true,
      "message": "Operation performed successfully",
      "data": [{
          "nick": "muquaddim1",
          "name": "Muquaddim One",
          "id": "141",
          "mobile": "01710000***",
          "email": "muquaddim+1@example.com",
          "create_time": "2012-02-26 14:58:29"
      }]
  }
  </code></pre>
  
  <h2>Store</h2>
  
  <pre><code>var user_store = Ext.create('Ext.data.Store', {
      // destroy the store if the grid is destroyed
      autoDestroy: true,
      autoLoad: true,
      model: 'XXX.User',
      sotreId: 'user-store',
      proxy: {
          type: 'ajax',
          url : 'proxy/user'
      },
      sorters: [{
          property: 'create_time',
          direction: 'ASC'
      }]
  });
  </code></pre>
  
  <h2>Grid</h2>
  
  <pre><code>var user_grid = Ext.create('Ext.grid.Panel', {
  title: 'List of Users',
      store: user_store,
      columns: [{
          header: 'Nick',
          dataIndex: 'nick',
          editor: {
              allowBlank: false
          }
      }, {
          header: 'Name',
          dataIndex: 'name',
          flex: 1,
          editor: {
              allowBlank: false
          }
      }, {
          header: 'Email',
          dataIndex: 'email',
          width: 160,
          editor: {
              allowBlank: false,
              vtype: 'email'
          }
      }, {
          header: 'Mobile',
          dataIndex: 'mobile',
          width: 100,
          editor: {
              allowBlank: false
          }
      }, {
          xtype: 'datecolumn',
          header: 'Join Date',
          dataIndex: 'create_time',
          width: 90,
          editor: {
              xtype: 'datefield',
              allowBlank: false,
              format: 'Y-m-d H:i:s',
              maxValue: Ext.Date.format(new Date(), 'Y-m-d H:i:s')
          }
      }]
  });
  </code></pre>
  
  <h2>Panel</h2>
  
  <pre><code>var users = Ext.create('Ext.panel.Panel', {
      title: 'Users',
      id: 'user_panel',
      items:[user_grid]
  });
  </code></pre>
  
  <p>I am using ExtJS 4.0.7. I modified the code found in Example. Example code works fine. But it does not work. What am I missing here?</p>