title: How can I add a "new tab" button next to the tabs of a QMdiArea in tabbed view mode?
body: <p>I'd like to have a "new tab" button much like Chrome or Firefox has for my <code>QMdiArea</code>.</p>
  
  <p>I can make a button or menu item somewhere that adds a new subdocument to the MDI thing, but how can I make it a visually appealing tiny tab with a "+" as label? Alternatively, I would be happy enough with a <code>QTabWidget</code> with such a button.</p>