vtkOpenGLState do not save front-facing polygons info
vtkOpenGLState
do not save the orientation of front-facing polygons.
auto ostate = this->GetState();
ostate->Push();
// Change FrontFace
ostate->Pop();
// FrontFace remains changed
vtkOpenGLState
is not exhaustive regarding all possible changes and it's probably just missing, so fixable easily.
Current workaround is simply to manually save FrontFace value then restore it with glGet/glFrontFace functions.