extjs treegrid displaying empty grid columns - extjs

Question

I am trying to get a really basic tree grid working but all I get is an empty panel.
I copied the json string from a working treepanel example and added the date and filename myself for the extra grids.
So calling the bits root and children worked for a basic panel (i had it working when it only had the field text and was directly in the store. So i presumed it would work for a tree grid.
After searching I found that a treestore doesn't have a data config it had to be moved to the proxy. Now I just have empty date and filename columns.
so here is my model
Ext.define('Coda.common.repository.model.RepositoryMaintModel',{
extend: 'Ext.data.Model',
fields: [
{name: 'date', type: 'string'},
{name: 'filename', type: 'string'},
{name: 'text', type: 'string'},
{name: 'iconCls' , type: 'string', defaultValue: 'treenode-no-icon'},
{name: 'expanded' , type: 'boolean', defaultValue: true, persist: false},
{name: 'index' , type: 'int'}
]
});
and here is my view
Ext.define('view.RepositoryMaintView', {
extend: 'U4.panel.Panel',
requires: ['Ext.layout.container.HBox',
'model.RepositoryMaintModel',
'Ext.tree.Panel'],
EVENT_DOWNLOAD: 'download',
layout: 'hbox',
constructor: function (config) {
var me = this;
me.addEvents(
/**
* #event download
* #param {view.RepositoryMaintView} when pressing the download button
*/
me.EVENT_DOWNLOAD
);
var data = {root: {
expanded: true,
root: [
{ text: "detention",date:'10-01-2013', filename:'boo.txt', leaf: true },
{ text: "homework",date:'10-01-2013', filename:'boo.txt', expanded: true,
root: [
{ text: "book report",date:'10-01-2013', filename:'boo.txt', leaf: true },
{ text: "algebra",date:'10-01-2013', filename:'boo.txt', leaf: true}
] },
{ text: "buy lottery tickets",date:'10-01-2013', filename:'boo.txt', leaf: true }
]
}};
var store = Ext.create('Ext.data.TreeStore', {
model: 'blah.blah.model.RepositoryMaintModel',
// data: data, <-- remove from here
proxy: {
type: 'memory',
data: data, // <-- place here
reader: {
type: 'json',
root: 'root'
}
},
folderSort: true
});
var center = Ext.create('Ext.tree.Panel',{
title: 'Folders Companies Items',
//region: 'center',
width: 1000,
height: 200,
collapsible: false,
useArrows: true,
rootVisible: false,
store: store,
multiSelect: true,
columns: [
{
xtype: 'treecolumn', //this is so we know which column will show the tree
text: 'hmm',
flex: 2,
sortable: true
},{
text: 'Date',
sortable: true,
dataIndex: 'date'
},{
text: 'filename',
sortable: true,
dataIndex: 'filename'
}]
});
me.items = [center];
me.callParent(arguments);
}
});