title: Why is window.opener undefined in this specific version of Windows/IE?
body: <p>My website depends on popups. Up until now I've been using <code>window.opener.location.reload()</code> to refresh the parent window, but all of a sudden my users are reporting that popups are not closing. Also, calling <code>window.close()</code> causes a "The webpage you are viewing is trying to close the tab" warning.</p>
  
  <p>I've managed to reproduce this issue in Windows 8.1 Pro Preview running IE 11.0.9431.228, but the problem does <em>not</em> occur in Windows 8.1 Enterprise Evaluation and IE 11.0.9600.16438.</p>
  
  <p>Has anyone else experienced this issue? Why would <code>window.opener</code> not be set? All popups are opened with <code>window.open</code>.</p>