title: Ignore and propagate QWidget click events to the OS
body: <p>I have a top-level parentless <code>QWidget</code> on top of which I have a bunch of other <code>QWidgets</code>(e.g. <code>QPushButton</code>s). I would like to make my <code>QWidget</code> act like it is transparent for mouse events. So when I click on the <code>QWidget</code>(but not on my buttons) I want my window to lose focus and something in the back to be selected(e.g. a Windows Explorer window if it happens to be in the back of my window). I also want my <code>QPushButton</code>s to continue processing mouse events.</p>
  
  <p>Is this possible? I tried setting the <code>Qt::WA_TranslucentBackground</code> and <code>Qt::WA_TransparentForMouseEvents</code> on the widget but if I draw something on it, e.g. a <code>QGraphicsDropShadowEffect</code> the widget still processes mouse click events on the parts where <code>QGraphicsDropShadowEffect</code> draws on it.</p>
  
  <p>Is this possible?</p>
  
  <p>Regards!</p>