Loosen a bit the HTML hierarchy required for Tabs to work, Improved UX of the dev tools

chrome/browser/resources/apps_debugger/background.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 var mainWindow = null;
 chrome.app.runtime.onLaunched.addListener(function() {
   if (mainWindow && !mainWindow.contentWindow.closed) {
     mainWindow.focus();
   } else {
     chrome.app.window.create('main.html', {
-      width: 768,
-      height: 1024,
+      id: 'apps_debugger',
+      minHeight: 600,
+      minWidth: 800,
+      height: 600,
+      width: 800,
     }, function(win) {
       mainWindow = win;
     });
   }
 });