Only set application menu on OS X.

browser/default_app/default_app.js

@@ -156,9 +156,12 @@ app.on('finish-launching', function() {
   ];
 
   menu = Menu.buildFromTemplate(template);
-  Menu.setApplicationMenu(menu);
+
+  if (process.platform == 'darwin')
+    Menu.setApplicationMenu(menu);
 
   ipc.on('message', function(processId, routingId, type) {
+    console.log(type);
     if (type == 'menu')
       menu.popup(mainWindow);
   });

browser/default_app/index.html

@@ -7,7 +7,6 @@
   This is the default mode of Atom Shell, please follow the instructions in
   wiki to get started.
   <script type="text/javascript" charset="utf-8">
-
     var ipc = require('ipc');
 
     window.addEventListener('contextmenu', function (e) {