Fit minimal size of a QDockPanel after QLabel content update

Question

I have a QDockWidget with a QGroupBox as the top widget, with QVBoxLayout applied. This contains a QChartView and a QLabel.

The QLabel contains a text composed of several lines of different length.

First, I would like to have the QChartView the same width and height as the QLabel.

Second, as the content of the QLabel is updated by setText(...) in a Slot method, its content changes in height and width. So I would like to update the width and height of the QChartView above it.

For the moment, I only achieved to grow the entire DockPanel to accomodate longer and wider QLabel content, but not to shrink back when this content is narrower and less wide...

I did play with a lot of things, without real success (here a snippet of the Slot method that updates the QLabel content...):

        self.fkChartView.hide()
        self.pPDetailsLabel.hide()
        self.pPDetailsLabel.parent().hide()
        self.pPDetailsLabel.setText(self.canvas.grayScottModel.getPearsonPatternDescription(specie=type))
        self.pPDetailsLabel.updateGeometry()
        self.pPDetailsLabel.parent().updateGeometry()
        self.pPDetailsLabel.parent().update()

        self.pPDetailsDock.updateGeometry()
        self.pPDetailsDock.update()

        self.pPDetailsLabel.show()
        self.pPDetailsLabel.parent().show()

        # print(self.pPDetailsLabel.sizeHint())
        self.fkChartView.setMinimumHeight(self.pPDetailsLabel.size().width())
        self.fkChartView.setMaximumHeight(self.pPDetailsLabel.size().width())
        self.fkChartView.setMinimumWidth(self.pPDetailsLabel.size().width())
        self.fkChartView.setMaximumWidth(self.pPDetailsLabel.size().width())
        self.fkChartView.updateGeometry()
        self.fkChartView.show()
        self.fkChartView.updateGeometry()
        self.fkChartView.update()

I tried to hide the widgets, so they forget their sizes and/or sizeHint (not sure). I tried a few updateGeometry() and update() too, but it does not seem to help.

An idea, anyone?