Face a crash problem in using "vtkProperty->Deepcopy()"

Development
1

I want to highlight the actor when I press my mouse’s left button. So I wrote a subclass of vtkInteractorStyle. The code lists here:

void ModelViewerInteractor::OnLeftButtonDown()
{
    vtkNew<vtkNamedColors> colors;
    int *clickPos = GetInteractor()->GetEventPosition();
    _Renderer->Render();
    vtkNew<vtkPropPicker> picker;
    picker->Pick(clickPos[0], clickPos[1], 0, _Renderer);
    if (LastPickedActor) {
        LastPickedActor->GetProperty()->DeepCopy(LastPickedProperty);
    }
    LastPickedActor = picker->GetActor();
    if (LastPickedActor) {
        LastPickedProperty->DeepCopy(LastPickedActor->GetProperty());
        LastPickedActor->GetProperty()->SetColor(colors->GetColor3d("blue").GetData());
        LastPickedActor->GetProperty()->SetOpacity(1.0);
    }
    vtkInteractorStyleTrackballCamera::OnLeftButtonDown();
}

But when the program run at the code “LastPickedProperty->DeepCopy(LastPickedActor->GetProperty());”, the program crashes.
So I changed the code, and just preserved color and transparency characteristics as this:

void ModelViewerInteractor::OnLeftButtonDown()
{
    vtkNew<vtkNamedColors> colors;
    int *clickPos = GetInteractor()->GetEventPosition();
    _Renderer->Render();
    vtkNew<vtkPropPicker> picker;
    picker->Pick(clickPos[0], clickPos[1], 0, _Renderer);
    if (LastPickedActor) {
        LastPickedActor->GetProperty()->SetColor(LastPickedProperty->GetColor());
        LastPickedActor->GetProperty()->SetOpacity(LastPickedProperty->GetOpacity());
    }
    LastPickedActor = picker->GetActor();
    if (LastPickedActor) {
        LastPickedProperty->SetColor(LastPickedActor->GetProperty()->GetColor());
        LastPickedProperty->SetOpacity(LastPickedActor->GetProperty()->GetOpacity());
        LastPickedActor->GetProperty()->SetColor(colors->GetColor3d("blue").GetData());
        LastPickedActor->GetProperty()->SetOpacity(1.0);
    }
    vtkInteractorStyleTrackballCamera::OnLeftButtonDown();
}

It still crash, and the variable “LastPickedProperty” has been initialized. I found if i run the code “LastPickedActor->GetProperty()->GetColor()”, the application will also crash.
Amazingly，sometimes, the application can run normally, but almost all the time the application
is unable to run properly.
Can any developer tell me the reason？Thank you!