Steps to reproduce:
- Open RigidRegistration view
- Load two images
- Activate checkbox 'Manual Registration'
- Move the slider labeled with 'y-Axis (Sagittal)'
--> Rotation is shown in coronal render window
- Move the slider labeled with 'x-Axis (Frontal)'
--> Rotation is shown in sagittal render window
I also suggest to rename 'Frontal' to 'Coronal' in order to be consistent with the render window labels.