I have a problem with the vtkScalarBarActor in RC1 of VTK9.0.
I am working with VTK libraries installed with ninja install. With VTK8.2 I am able to create a subclass of vtkScalarBarActor and access the pointer to the protected member
vtkScalarBarActorInternal* P by including vtkScalarBarActorInternal.h in my cpp file.
With VTK9.0 RC1 this is not possible anymore because vtkScalarBarActorInternal.h is set as a PRIVATE_HEADER in Rendering/Annotation/CMakeLists.txt and therefore not included in the installed VTK.
Is this behavior intended? If yes, what is the correct way of accessing the internal state of vtkScalarBarActor from a subclass?