Update app.js to replace the obsolete Ext.EventManager.

static/app.js

@@ -32,7 +32,8 @@ Ext.onReady(function(){
     // Action trigger when the page is refreshed or when the tab is closed.
     // NOTE: It should work when the browser is closed to.
     // Not working with FireFox 17.0.8, web2py 2.4.5 and Ext JS 3.4.0.
-    Ext.EventManager.on(window, 'beforeunload', Dbui.closeUserSession);
+    // nor with Firefox 38, web2py 2.14.6, Ext JS 6.0.1
+    Ext.getWin().on('beforeunload', Dbui.closeUserSession);
 
 	// Instantiate the application
 	app = Ext.create('Dbui.container.Viewport', Dbui.config.viewport);