QwtPlot width not accepting more than 32800. Is it a bug?

[rawfool]

I'm using QwtPlot to draw a Histogram(eg given in TVplot). I'm placing this QwtPlot(size = 32000, 290) on QScrollArea(size = 550, 300).
I'm plotting 10000 values. But when I'm increasing the width to any value above 32800, it's showing a black area after that. So the values are also not visible in that black area. Is this function limited to that width? What would be alternative solution?

class GraphWidget : public QwtPlot
{
    Q_OBJECT
public:
    explicit GraphWidget(QWidget *parent = 0);
 
signals:
 
public slots:
 
};

class GraphWidget : public QwtPlot
{
    Q_OBJECT
public:
    explicit GraphWidget(QWidget *parent = 0);
    
signals:
    
public slots:
    
};

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