title: How to allow resizing of QMessageBox in PyQt4
body: <p>I'm using the nice feature in QMessageBox to optionally show detailed text to the user. However, the window after expansion is still fairly small, and one immediately tries to resize the window so more of the details are visible. Even after setting what I think are the proper settings it won't allow resizing.</p>
  
  <p>Here's the relevant snippet of PyQt4 code:</p>
  
  <pre><code>mb = QMessageBox()
  mb.setText("Results written to '%s'" % filename)
  mb.setDetailedText(str(myData))
  mb.setSizePolicy(QSizePolicy.Expanding, QSizePolicy.Expanding)
  mb.setSizeGripEnabled(True)
  </code></pre>
  
  <p>Am I missing a step and/or is this at all possible?</p>