title: In Qt Qml Controls, ApplicationWindow lacks the native-looking theme when run
body: <p>Qml Controls comes with a nice native-like theme by default. When I run my program as qml files through the interpreter, it looks great, however, once I copy my code over to c++ backend and build it, it looks completely unthemed and very bland. Also I did not enable any sort of Control Styles to void the native looking theme.</p>
  
  <p>The only thing that I changed was since my root object in my main qml file is a ApplicationWindow, I changed the main.cpp file from loading qmlviewer, to creating my own application engine. I was thinking that this might be the issue but i'm not sure.</p>
  
  <pre><code>#include &lt;QGuiApplication&gt;
  #include &lt;QQmlApplicationEngine&gt;
  #include &lt;QQuickWindow&gt;
  
  int main(int argc, char *argv[]) {
      QGuiApplication app(argc, argv);
      QQmlApplicationEngine engine;
  
      engine.load(QUrl("src/qml/main.qml"));
      QObject *topLevel = engine.rootObjects().value(0);
      QQuickWindow *window = qobject_cast&lt;QQuickWindow *&gt;(topLevel);
  
      window-&gt;show();
      return app.exec();
  }
  </code></pre>