First Click of a QwtPlotPicker does not respond

[jbob99]

Hi fellow coders:


I am working on a bit of code where I need to find the coordinates of a mouse click on a QwtPlot object. Everything works fine except the very first mouse click is ignored. Here is the initialization code:

// code snippet  ---------------------------------------------------------------------------------
    picker = new QwtPlotPicker(btrElement->btrStructure.btr->canvas());
    picker->setEnabled(true);
    picker->setTrackerPen(QColor(Qt::white));
    picker->setTrackerMode(QwtPlotPicker::AlwaysOn);
    picker->setStateMachine(new QwtPickerClickPointMachine());
    picker->setRubberBand(QwtPicker::RectRubberBand);
    connect(picker,
            SIGNAL(selected(QPointF)),
            this,
            SLOT(rcvBTRPointSelected(QPointF)));

// code snippet  ---------------------------------------------------------------------------------
    picker = new QwtPlotPicker(btrElement->btrStructure.btr->canvas());
    picker->setEnabled(true);
    picker->setTrackerPen(QColor(Qt::white));
    picker->setTrackerMode(QwtPlotPicker::AlwaysOn);
    picker->setStateMachine(new QwtPickerClickPointMachine());
    picker->setRubberBand(QwtPicker::RectRubberBand);
    connect(picker,
            SIGNAL(selected(QPointF)),
            this,
            SLOT(rcvBTRPointSelected(QPointF)));

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I would expect that once I click on the QwtPlot object, it would immediately respond to the click via the SLOT/SIGNAL mechanisms that Qt uses. This does happen after the initial click.
As another note: I am using 5 of these plots and each exhibits the very same behavior.
Any help would be greatly appreciated. Thanks.

-jbob