vtkLineWidget2/vtkLineRepresentation/probeFilter returns 0-s
We use vtkLineWidget2 combined with probeFilter to "cross cut" 2d image.
In VTK7 it worked fine In VTK8 we periodically get 0-s instead of pixel values of the image. It seems that we can always move one end of LineWidget and get a correct cross-cut. But when we try to move the other end, we can sometimes get all 0-s from probeFilter. The Line widget then needs to be disabled and re-enabled to start getting the correct values again.