Hello,
I have posted a lot and I got a lot of help here. I need another one. I'm plotting graphs with dotted line and tracking using QwtPlotPicker, but it tracks the plot area and I would like to track only some selected points. My code to track the whole area is:

Qt Code: 
  1. picker = new QwtPlotPicker(QwtPlot::xBottom, channelSelection->currentIndex(),
  2. 		QwtPlotPicker::CrossRubberBand, QwtPicker::AlwaysOn,
  3. 		plot->canvas());
  4. picker->setStateMachine(new QwtPickerDragPointMachine());
  5. picker->setRubberBandPen(QColor(Qt::darkMagenta));
  6. picker->setRubberBand(QwtPicker::CrossRubberBand);
  7. picker->setTrackerPen(QColor(Qt::green));
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As I said, this code tracks the whole plotting area and I want to track just some points that I have saved in my QVector. For example, the draw below is showing the picker tracking some part of the plotting area and showing the x and y axis value:

trackNow.jpg

And I would like to show the value according by the points that I have, the tracking would show something just when the mouse is on the place that the point is equal to some point of my vector. I have the line and the dots, the dots are my values, when the user pass the mouse on a dot the picker would show the value:

rightTrack.jpg

Is it possible to enable the picker just for some points? If yes, someone can help me giving me a tipp, I have no idea how to set the picker to track just some selected points.
Thanks in advance
Best Regards