title: How to set selected filter on QFileDialog?
body: <p>I have a open file dialog with three filters:</p>
  
  <pre><code>QString fileName = QFileDialog::getOpenFileName(
          this,
          title,
          directory,
          tr("JPEG (*.jpg *.jpeg);; TIFF (*.tif);; All files (*.*)")
  );
  </code></pre>
  
  <p>This displays a dialog with "JPEG" selected as the default filter. I wanted to put the filter list in alphabetical order so "All files" was first in the list. If I do this however, "All files" is the default selected filter - which I don't want.</p>
  
  <p>Can I set the default selected filter for this dialog or do I have to go with the first specified filter?</p>
  
  <p>I tried specifying a 5th argument (<code>QString</code>) to set the default selected filter but this didn't work. I think this might only be used to retrieve the filter that was set by the user.</p>