title: QComboBox drop-down list adding unnecessary scroll bar
body: <p>I'm creating a <code>QComboBox</code> in an app with just 2 items in it. This should appear without a scroll bar, but it seems to be creating the drop-down list very fractionally too small for the information in it, causing it to create a vertical scroll bar.</p>
  
  <p>It feels as though it's slightly mis-read the text size when calculating the size of the created list.</p>
  
  <p>Any idea how to get around this?</p>