I need to get x and y coordinates of mouse click on QwtPlot drawing area (not the whole widget!). The problem is that there's only method `bool event(QEvent*)` that is called on every event. I've found some solutions (<http://www.qtcentre.org/archive/index.php/t-9502.html>), using QwtPlotPicker but that doesn't work for me, I'm using Qwt 6 and there are no such methods like `setSelectionState()`. 

What is other methods for achieving mouse click events on drawing area in QwtPlot?