Please help with Tree

//x:\home\localhost\www\assets\components\tests\js\mgr\widgets\home.panel.js
Tests.panel.Home = function(config) {
    config = config || {};

Ext.apply(config,{
        border: false
        ,baseCls: 'modx-formpanel'
        ,items: [
	        {                    //tittle
	            html: '<h2>'+_('tests.management')+'</h2>'
	            ,border: false
	            ,cls: 'modx-page-header'
	        },
	        {        //wrapper
	        xtype: 'panel'
	        ,layout: 'hbox'
	        ,items:
	           [


	           {          //tree
	           xtype: 'treepanel',
	           region: 'west',
		       width: 200,
		       autoScroll: true,
		       split: true,
		       bodyBorder :false,
		       hideCollapseTool:true,
		       rootVisible: true,    /*  */

		        loader: aa=new Ext.tree.TreeLoader({
						dataUrl: '../core/components/tests/processors/mgr/test/get_tree.php'
				}),
				listeners: {
		            click: function(n) {

		                Ext.Msg.alert('Navigation Tree Click', 'You clicked: "' + n.attributes.text + '"');
		            }
		        },

				root: new Ext.tree.AsyncTreeNode({
						expanded: true,
						text: _('tests'),
		        		draggable: false,
		        		id: 'source'
					 }),
	        	},



	            //modxTabs
	        	{
	            xtype: 'modx-tabs',
	            bodyStyle: 'padding: 10px',
	            defaults: { border: false ,autoHeight: true },
	            border: true,
	            items: [{
	                title: _('tests'),
	                defaults: { autoHeight: true },
	                items: [{
	                    html: '<p>'+_('tests.management_desc')+'</p>
',
	                    border: false
	                	},
	                	{
	                    xtype: 'tests-grid-tests',
	                    preventRender: true
	                }]
	            }]
	        	}//modxTabs    */
	            ]
	          } //wrap
	     ]
	    }
  );

    Tests.panel.Home.superclass.constructor.call(this,config);
};
Ext.extend(Tests.panel.Home,MODx.Panel);
Ext.reg('tests-panel-home',Tests.panel.Home);

          <?
          //x:\home\localhost\www\core\components\tests\processors\mgr\test\get_tree.php


   $sampleArr =  array( array( id=>1, 'text'=>"Node 1", leaf=>true),  array( id=>2, 'text'=>"Node 2", leaf=>true )      );
   echo json_encode($sampleArr); 
   return '';

$$isLimit = !empty($scriptProperties['limit']);
$start = $modx->getOption('start',$scriptProperties,0);
$limit = $modx->getOption('limit',$scriptProperties,20);
$sort = $modx->getOption('sort',$scriptProperties,'name');
$dir = $modx->getOption('dir',$scriptProperties,'ASC');
$query = $modx->getOption('query',$scriptProperties,'');

/* build query */

$c = $modx->newQuery('Test');

if (!empty($query)) {
    $c->where(array(
        'name:LIKE' => '%'.$query.'%',
        'OR:description:LIKE' => '%'.$query.'%',
    ));
}

$count = $modx->getCount('Test',$c);
$c->sortby($sort,$dir);
if ($isLimit) $c->limit($limit,$start);
$tests = $modx->getIterator('Test', $c);

/* iterate */

$list = array();
foreach ($tests as $test) {
    $testArray = $test->toArray();

    $list[]=array(id=> $testArray['id'], text=> $testArray['name'], leaf=> true,);
}
return $this->outputArray($list,$count);