title: JSpinner takes up entire width in JOptionPane
body: <p>I'm trying to put a JSpinner in a JOptionPane as follows,</p>
  
  <pre><code>        SpinnerModel saModel = new SpinnerNumberModel(11, 1, 36, 1);
          JSpinner saSpinner = new JSpinner(saModel);
          Dimension d = saSpinner.getSize();
          d.width = 20;
          saSpinner.setSize(d);
  
          Object[] message = { "Choose the key number for sa.", saSpinner };
  
          JOptionPane optionPane = new JOptionPane(message,
                  JOptionPane.PLAIN_MESSAGE, JOptionPane.OK_CANCEL_OPTION);
          JDialog dialog = optionPane.createDialog(frame, "Change Sa Key");
          dialog.setVisible(true);
  </code></pre>
  
  <p>This works, but the only issue is that the JSpinner fills the width of the Dialog regardless of the size I set. I've tried using setPreferredSize() as well. How do I fix this?</p>