ExtJs 5: TreePanel: Not getting the default leaf icons and lines

I created a sample TreePanel using Sencha ExtJs 5. I followed the sample example in the documentations and I am able to see the items (leaves and branches) but they are not coming as a Tree, but as a list.

Here is my code:

Store:

Code:

Ext.define('MyApp.store.ResourcesStore', 
{extend : 'Ext.data.TreeStore',
root : {    
expanded : true,   
 children : [ {       
text : "UI Forms",       
 leaf: false,        
expanded : true,        
children : [ {           
 text : "Web",            
leaf : true        
}, {            
text : "Smart Phone",            
leaf : true        
}, {            
text : "Tablet",            
leaf : true        
} ]    
}, {        
text : "Reports",        
leaf : true    
}, {       
 text : "Dashboards",        
leaf : true    
}, {       
 text : "Entities",        
leaf : true    
}, {        
text : "Queries",        
leaf : true    
}, {        
text : "Services",        
leaf : true    
} 
]}});

View:

Code:

Ext.define('MyApp.view.leftpanel.ResourcesView', {
extend : 'Ext.TreePanel',
xtype : 'resources-panel',
title : 'Resources',
store : 'ResourcesStore',
rootVisible : false
});

Here is what my output looks like:

v33im.png