_planeWidgetX->AddObserver(vtkCommand::InteractionEvent, wlipwc );
_planeWidgetY->AddObserver(vtkCommand::InteractionEvent, wlipwc );
_planeWidgetZ->AddObserver(vtkCommand::InteractionEvent, wlipwc );
_planeWidgetX->AddObserver(vtkCommand::InteractionEvent, wlipwc );
_planeWidgetY->AddObserver(vtkCommand::InteractionEvent, wlipwc );
_planeWidgetZ->AddObserver(vtkCommand::InteractionEvent, wlipwc );