The QmitkImageNavigatorView heavily depends on the three different render windows. It uses the view directions as strings (see T25595: [Multi widget] Make classes work with the new render window access) and provides three fixed navigation widgets for the different views.

It might make sense to provide a special image navigator that can work with the MxNMultiWidget to provide a "global" crosshair navigation. For this T26543: Enum for AXIAL, SAGITTAL, CORONAL 3D/ORIGINAL/NONE is provided at many different locations should be fixed.