Adjusts the size of this widget as the parent resizes.

def adjustSize(self):
        """
        Adjusts the size of this widget as the parent resizes.
        """
        # adjust the close button
        align = self.closeAlignment()
        if align & QtCore.Qt.AlignTop:
            y = 6
        else:
            y = self.height() - 38

        if align & QtCore.Qt.AlignLeft:
            x = 6
        else:
            x = self.width() - 38

        self._closeButton.move(x, y)

        # adjust the central widget
        widget = self.centralWidget()
        if widget is not None:
            center = self.rect().center()
            widget.move(center.x() - widget.width() / 2, center.y() - widget.height() / 2)