title: QCalendarWidget as "Pop-up", not as new Window?
body: <p>I want to create a Settings-Widget, where I can choose a Date.<br>
  Because it isn't nice to create 3 QLineEdits to call the QDate-Constructor with QDate(int year, int month, int day), I thought it would be better, if you can push a "show calendar"-Button for example, where you can choose the date.<br>
  But I don't want to show this calendar in a new Window, I want to show it as a "Pop-up" (I don't know how to explain this), which you might know for example from the OpenOffice-Settings.<br>
  You have any idea how to implement that?</p>