pyqtgraph/pyqtgraph — pull request #25 by vasole (2014-01-14 10:32:43+00:00)
Title: Allow use of derived classes and add missing argument

Unless one can recover the last event handled by the PlotCurveItem or the ScatterPlotItem, it is impossible to recover things like what mouse button was pressed and so on. The proposed modification allows to use derived classes of PlotDataItem, PlotCurveItem and ScatterPlotItem to handle events in a different manner.