title: Qt 5.9.0 to 5.9.4 work fine, but Qt 5.9.5 and 5.9.6 have issues
body: <p>I'm playing around with this repo: <a href="https://github.com/qt-labs/qt3d-editor" rel="nofollow noreferrer">https://github.com/qt-labs/qt3d-editor</a></p>
  
  <p>My observation:</p>
  
  <ol>
  <li>When using Qt 5.9.0, 5.9.1, 5.9.2, 5.9.3 and 5.9.4, the application can import files, like STL. </li>
  <li>But with Qt 5.9.5 and 5.9.6 the application <strong>cannot</strong> import any file, it gets stuck in import process and never finishes importing. Also, the same issue happens when working with Qt 5.11. </li>
  </ol>
  
  <p>I assume it might be related to Qt3D module. The <a href="http://code.qt.io/cgit/qt/qt3d.git/tree/dist/changes-5.9.5/?h=v5.9.5" rel="nofollow noreferrer">5.9.5 change log for Qt3D</a> mentions that only minor code improvements are done. Can anybody give a <em>hint</em> why this is happening?</p>
  
  <hr>
  
  <p>The screen shot of import button getting stuck is shown below:</p>
  
  <p><a href="https://i.stack.imgur.com/h3x8v.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/h3x8v.png" alt="screen shot of import button getting stuck"></a></p>