title: Loading Nested JSON Data in ExtJS4 TreeGrid
body: <p>I'm trying to load nested JSONData into my tree grid. On the first call to get data, all the data needed to populate the grid is returned in the response as a JSON Object. However I can see that it still tries fetch data for all the parent objects in the grid.</p>
  
  <p>Even after the spurious GETs, it is still unable to populate the child Nodes.</p>
  
  <p>I've defined 2 models, the parent  with a "hasMany" relationship referring to the child model, and the child node with "BelongsTo" relationship referring to the parent model</p>
  
  <p>I'm using an Ajax Proxy with a JSON reader.</p>
  
  <p>Searching the web I can't find much information and I've used the user-orderitems-products example  in the extJS documentation to try and set up the my models and tree.</p>
  
  <p>I'm not entirely sure what I'm missing. Any assistance would be much appreciated.</p>
  
  <p>JSON (person may or may not have children objects):</p>
  
  <pre><code>People: {
   {firstName: john, id:123, uniqueID:1231, leaf:true},
   {firstName: jane, id:124, uniqueID:1240, 
    offspring:[
      {firstName: adam,    id:124,  uniqueID:1241, leaf:true},
      {firstName: brandon, id:124,  uniqueID:1242, leaf:true},
      {firstName: claire,  id:1243, uniqueID:1243, leaf:true}
   ]}
  }
  </code></pre>
  
  <p>Model:</p>
  
  <pre><code>Ext.define('Person',{
    extend: 'Ext.data.Model',
    fields: [
      {name: 'firstName', type:'string'},
      {name: 'uniqueID',  type:'float'}
      hasMany: {
         model:'Offspring', 
         name: 'Offspring', 
         associationKey: 'offspring',
         primaryKey: 'uniqueID',
         foreignKey: 'id'
      }
    ],
    proxy: {
     type: 'rest',
     url: 'http://blah/blah',
     reader: {
       type: 'json',
       root: 'People'
     }
  
    }
  });
  
  Ext.define('Offspring',{
    extend: 'Ext.data.Model',
    fields: [
      {name: 'firstName', type:'string'},
      {name: 'uniqueID',  type:'float'}
   ],
   belongsTo: 'Person'
  });
  </code></pre>
  
  <p>Store Definition:</p>
  
  <pre><code>var store = Ext.create('Ext.data.TreeStore', {
    model: 'Person',
    folderSort: true
  }
  </code></pre>