Sets the central widget that will be used by this popup.
        
        :param      widget | <QWidget> || None

def setCentralWidget( self, widget ):
        """
        Sets the central widget that will be used by this popup.
        
        :param      widget | <QWidget> || None
        """
        self._scrollArea.takeWidget()
        self._scrollArea.setWidget(widget)
        
        self.adjustSize()