title: Dialog with statusbar
body: <p>I need to use a dialog with a statusbar. I don't know how can I use it in <code>QDialog</code> so I use <code>QMainWindow</code>. But <code>QMainWindow</code> doesn't have <code>exec()</code> function and <code>show()</code> function works asynchronously.</p>
  
  <p>I use <code>QtDesigner</code> and I did not understand how can I add statusbar using it. I also want to see status tips of widnow's widgets in this statusbar.</p>