title: SAPUI5: issue about function navButtonPress
body: <p>I'm using SAPUI5 for a web site using Javascript method.</p>
  
  <p>Since version 1.28.9 of SAPUI5, using the function "navButtonPress" the web site go back to the previous page.</p>
  
  <p>From version 1.30, the "navButtonPress" function does not work anymore (it reloads the page and restarts the web site).</p>
  
  <p>This is a portion of code:</p>
  
  <pre><code>var pgDettaglioCliente = new sap.m.Page("pgDettaglioCliente", {  
      title: get("titleDettaglio"),  
      showHeader: true,  
      showNavButton: true,  
      navButtonPress: function () {  
          app.to("pgRiepilogoTicket");  
      },  
      content: new sap.m.Panel("pDettaglioCliente", {  
          content: [formDettaglioCli()]  
      })  
  });
  </code></pre>
  
  <p>Any ideas?</p>