title: ExtJs 5: TreePanel: Not getting the default leaf icons and lines
body: <p>I created a sample <code>TreePanel</code> 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.</p>
  
  <p>Here is my code: </p>
  
  <p>Store:</p>
  
  <pre><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
      } ]
  }
  });
  </code></pre>
  
  <p>View: </p>
  
  <pre><code>Ext.define('MyApp.view.leftpanel.ResourcesView', {
  extend : 'Ext.TreePanel',
  xtype : 'resources-panel',
  title : 'Resources',
  store : 'ResourcesStore',
  rootVisible : false
  });
  </code></pre>
  
  <p>Here is what my output looks like:</p>
  
  <p><img src="https://i.stack.imgur.com/v33im.png" alt="enter image description here"></p>
  
  <p>After executing the <code>sencha app build</code> command:
  Accordion panel got impacted.</p>
  
  <p><img src="https://i.stack.imgur.com/MOtQq.png" alt="enter image description here"></p>