Install Event Filter instead of PlotPanner

[missoni]

Hey!
I had been trying to modify QwtPlotPanner to repaint plot canvas during panning, until I read that this is impossible and I should install an event filter instead, which would catch mouse clicks and repaint the plot using setAxisScale(). I did this, but I the event filter is not called. My code is like the following:

Plot::Plot(QWidget *parent):
    QwtPlot(parent)
{
        ...
        createAxes();
        createLegend();
	installEventFilter(m_eventFilter);
        ...
        installPlotZoomer();
        installPlotPicker();
}

Plot::Plot(QWidget *parent):
    QwtPlot(parent)
{
        ...
        createAxes();
        createLegend();
	installEventFilter(m_eventFilter);
        ...
        installPlotZoomer();
        installPlotPicker();
}

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where event filter is the following short calss:

class MyEventFilter : public QObject
{
protected:
	bool eventFilter(QObject *, QEvent *) {
	        std::cout << "MyEventFilter::eventFilter()" << std::endl;
	        return true;
        }
};

class MyEventFilter : public QObject
{
protected:
	bool eventFilter(QObject *, QEvent *) {
	        std::cout << "MyEventFilter::eventFilter()" << std::endl;
	        return true;
        }
};

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MyEventFilter is not called. Any ideas why not?

Thank you in advance!