title: QML Window opacity doesn't work when fullscreen
body: <p>I've experienced a strange problem: when a QML <code>Window</code> is fullscreen, its <code>opacity</code> property doesn't work, so the window stay opaque. When the window isn't fullscreen (e.g. maximized), it works properly.</p>
  
  <p>Do you have any ideas how to deal with this problem?
  In fact, I want to animate fullscreen window fading in.</p>
  
  <p><strong>The code:</strong></p>
  
  <p><em>main.qml</em></p>
  
  <pre><code>import QtQuick 2.2
  import QtQuick.Controls 1.1
  import QtQuick.Window 2.1
  
  Window {
      visible: true
      visibility: "FullScreen"
  
      opacity: 0.5
  
      Text {
          id: text
          text: "Hello World"
          font.pointSize: 36
          color: "#333"
      }
  }
  </code></pre>
  
  <p><em>main.cpp</em></p>
  
  <pre><code>#include &lt;QApplication&gt;
  #include &lt;QQmlApplicationEngine&gt;
  
  int main(int argc, char *argv[])
  {
      QApplication app(argc, argv);
  
      QQmlApplicationEngine engine;
      engine.load(QUrl(QStringLiteral("qrc:///main.qml")));
  
      return app.exec();
  }
  </code></pre>
  
  <p>I use Qt 5.3 on Windows 8.1.</p>