MRView: tiny bug fix for starting in ortho view
MRView: tiny bug fix for starting in ortho view

Would otherwise prevent image from appearing due to focus remaining
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MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3