when i change the vtkWidgetEvent::Select of “this->CallbackMapper->SetCallbackMethod(vtkCommand::LeftButtonPressEvent, vtkWidgetEvent::Select, this,EllipseWidget::SelectAction);” to vtkWidgetEvent::AddPoint,my program will occur some strange Phenomenon.but when i see the sourcecode of vtk, i did’nt find any usage of vtkWidgetEvent,they are just to be map to a map[vtkCommand,vtkWidgetEvent],and map the [vtkWidgetEvent,callback function].in this section,i did’nt see the function of vtkWidgetEvent,seem’s remove it and map [vtkCommand,callback function] is a substitute.but then why can’t i change the Select to any other vtkWidgetEvent?how doest it works?thank you.i’ actually confused about it for a long time.