title: Sencha Touch - another view not showing on the tab panel
body: <p>I have an issue with showing a settings view on the main view when clicking a proper tab. Here is the code for the main view:</p>
  
  <pre><code>Ext.define('App.view.Main', {
  extend:'Ext.tab.Panel',
  requires: [
      'App.view.SettingsView'
  ],
  config: {
      fullscreen: true,
      tabBarPosition: 'bottom',
  
      items: [
          {
              title: 'About',
              iconCls: 'info',                
              items: {
                  docked: 'top',
                  xtype: 'titlebar',
                  title: 'Home Screen'
              },
              html: 'Home Screen'
          },
          {
              title: 'Maps',
              iconCls: 'maps',
              items:
                  {
                      docked: 'top',
                      xtype: 'titlebar',
                      title: 'Maps Screen'
                  },
                  html: 'Maps Screen'         
          },
          {
              title: 'Setiings',
              iconCls: 'settings',
              items: [
                  {
                      docked: 'top',
                      xtype: 'titlebar',
                      title: 'Settings'
                  },
                  {
                      xtype: 'settingsview',
                      id: 'settingsview'
                  }
              ]
          }
      ]
  }
  });
  </code></pre>
  
  <p>And this is the code for the settings view:</p>
  
  <pre><code>Ext.define('App.view.SettingsView', {
  extend: 'Ext.form.Panel',
  xtype: 'settingsview',
  
  requires: [
      'Ext.form.FieldSet',
      'Ext.field.Toggle',
      'Ext.field.Select',
      'Ext.field.Text',
      'Ext.Button'
  ],
  
  config: {
  
      xtype: 'fieldset',
      title: 'SettingsView',
      instructions: 'In case you do not want the app to detect your location you can enter the city and country.',
  
      items: [
          {
              name: 'geo',
              xtype: 'togglefield',
              label: 'Auto detect?',
              labelWidth: '55%',
              value: '1',
          },
          {
              name: 'units',
              xtype: 'selectfield',
              label: 'Units',
  
              options: [
                  {
                      text: 'Fahrenheit',
                      value: 'f'
                  },
                  {
                      text: 'Celsius',
                      value: 'c' 
  
                  }
              ]
  
          },
          {
              name: 'city',
              xtype: 'textfield',
              label: 'City',
              disabled: true
          },
          {
              name: 'country',
              xtype: 'textfield',
              label: 'Country',
              disabled: true
          },
          {
              xtype: 'button',
              text: 'Refresh',
              action: 'refresh',
              margin: '10 5',
              ui: 'confirm'
          }
      ]        
  }
  });
  </code></pre>
  
  <p>When the settings tab is enabled it shows only the title bar and the tab bar. No error messages. What am I doing wrong? </p>