title: Need something like a finished-signal from QWidget
body: <p>I'm searching for something like the finished-signal from <code>QDialog</code>, only for <code>QWidget</code>. The reason is, I disable my toolbar once the widget pops up (which isn't a problem at all) and I want the toolbar to be enabled again, once the widget is closed.</p>
  
  <p>I also can't override the close-Event of that widget, because then we would have GUI-code in business-classes.</p>