title: manually go back into previous screen in sencha touch
body: <p>I have a custom title bar as follows where i have 3 buttons </p>
  
  <pre><code>1) which leads to previous screen
  2) back record 
  3) next record 
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/lTD3u.png" alt="enter image description here"></p>
  
  <p>here is the code of custom titlebar </p>
  
  <pre><code>     {
          xtype : 'titlebar',
          title : 'Contacts',
          items : [{
  
                    ui:'back',text:'-', aling: 'left'  , action:'fback'
  
              },{
                  ui: 'back', text: 'back', align : 'left', action: 'back'
              },{
                  ui: 'forward', text: 'next', align : 'right', action: 'next'
              }]
      }
  </code></pre>
  
  <p>now when i catch the event in controller for <code>fback</code> i am firing <code>history.back()</code> to go back to the previous screen , but its not working even <code>tap</code> event is firing. </p>
  
  <p>i am using this custom title because i dont how to add <code>prev</code> and <code>next</code> button in <code>navigation view</code></p>