QwtPlot crash in Mac OS X

Hello Qt gurus,

I have written a code that runs a step by step analysis and in after each step, updates a plot of the results. For the plot, I have sub-classed QwtPlot as follows:

Code:

RPlotWidget::RPlotWidget(QWidget *parent)
   : QwtPlot(parent)
{
   setCanvasBackground(QColor(Qt::white));
   QwtLegend *legend = new QwtLegend(this);
   insertLegend(legend, QwtPlot::TopLegend);
   setMargin(5);
   setCanvasLineWidth(0);
   plotLayout()->setCanvasMargin(0);
   plotLayout()->setSpacing(0);
 
   QFont labelFont("Times New Roman", 10);
   setAxisFont(QwtPlot::xBottom, labelFont);
   setAxisFont(QwtPlot::yLeft, labelFont);
 
   QFont titleFont("Times New Roman", 12, QFont::Bold);
   QwtScaleWidget *bottomAxis = axisWidget(QwtPlot::xBottom);
   QwtText bottomText = bottomAxis->title();
   bottomText.setFont(titleFont);
   bottomAxis->setTitle(bottomText);
   bottomAxis->setMargin(0);
 
   QwtScaleWidget *leftAxis = axisWidget(QwtPlot::yLeft);
   QwtText leftText = leftAxis->title();
   leftText.setFont(titleFont);
   leftAxis->setTitle(leftText);
   leftAxis->setMargin(0);
 
   QwtPlotMagnifier *plotMagnifier = new QwtPlotMagnifier(canvas());
   plotMagnifier->setEnabled(true);
   plotMagnifier->setMouseButton(Qt::MidButton);
 
   QwtPlotPanner *plotPanner = new QwtPlotPanner(canvas());
   plotPanner->setEnabled(true);
   plotPanner->setMouseButton(Qt::LeftButton);
 
   QwtPlotZoomer *plotZoomer = new QwtPlotZoomer(canvas(), true);
   plotZoomer->setMousePattern(0, Qt::LeftButton, Qt::ControlModifier); 
   plotZoomer->setMousePattern(1, Qt::NoButton); 
   plotZoomer->setMousePattern(2, Qt::NoButton);
   plotZoomer->setEnabled(true);
}

I am using the above class in my analysis as follows:

Code:

// Declare the plotting variables
   QPointer<QwtPlot> thePlot = 0;
   QwtPlotCurve *y1Curve = 0;
   QwtPlotCurve *y2Curve = 0;
   QVector<double> xVector;
   xVector.append(0.0);
   QVector<double> y1Vector;
   y1Vector.append(0.0);
   QVector<double> y2Vector;
   y2Vector.append(0.0);
 
   int x = 0;
 
   while (x <= maxIterations) //Stop condition of the analysis
   {      
      x++;
 
      // Instatiating thePlot
      if (!thePlot) {
         thePlot = new RPlotWidget(mainWindow);
         thePlot->show();
         thePlot->setAxisTitle(QwtPlot::xBottom, "x");
         thePlot->setAxisTitle(QwtPlot::yLeft, "y");
 
         // Instantiating two curves
         y1Curve = new QwtPlotCurve(QString("y1"));
         y1Curve->setPen(QColor(Qt::red));
         y1Curve->setRenderHint(QwtPlotItem::RenderAntialiased, true);
         y1Curve->attach(thePlot);
 
         y2Curve = new QwtPlotCurve(QString("y2"));
         y2Curve->setPen(QColor(Qt::blue));
         y2Curve->setRenderHint(QwtPlotItem::RenderAntialiased, true);
         y2Curve->attach(thePlot);
      }
 
      double y1, y2;
 
      // ... Run the analysis, evaluate y1 and y2
 
      // Updating the plotting value vectors
      xVector.append(x);
      y1Vector.append(y1);
      y2Vector.append(y2);
 
      // Updating the plot
      y1Curve->setData(xVector, y1Vector);
      y2Curve->setData(xVector, y2Vector);
      thePlot->replot();
   }

This code works perfectly in Windows, but it crashes while running the "setData(...)" for the second iteration in Mac OS X. I have gone through all the threads about Qwt and Mac, yet I have not found any solutions :(.

I am using Qt 4.5.2 and Qwt 5.2.0. The Qwt is built statically.

Thanks a lot for any help in advance.
Mojtaba