From mitk-users: [ reported 08-11-2011 ]
"Minor issue... When I restrict the visible files in the file open dialog of ExtApp to "Nearly Raw Raster Data", it only shows .nrrd files. Shouldn't it also show .nhdr files? I see the "NRRD Vector Images" option correctly shows .nhdr files."
Obviously the 'Nearly Raw Raster Data' choice is not necessary, since the 'NRRD Vector Images' covers the right subset ( nhdr and nrrd files )