title: extjs store error handling
body: <p>I am trying to handle an exception in an <code>Ext.data.Store</code> instance when creating a new <code>Ext.data.Record</code>. When the server responds with the following json:</p>
  
  <pre><code>{"success": false, "message": "some text"}
  </code></pre>
  
  <p>I get an exception of type 'request', even though the server returns an HTTP 200 Response!</p>
  
  <p>To get a 'remote' error I have to create an object with the <code>root</code> property </p>
  
  <pre><code>({
      "success": false,
      "message": "some text",
      "data": {
          "PositionId": "00000000-0000-0000-0000-000000000000",
          "Name": "123"
      }
  })
  </code></pre>
  
  <p>...but I don't want this. Is there any way to change this behaviour?</p>
  
  <p>Also, when I insert a record in the store, it is automatically added to the associated grid, but if an error occurs it remains there, so I need to reload store on every error. Is there any better way to do this?</p>