Status: If a registration is selected the mapper deduces the reference input by using the target input of the registration algorithm (if this input is in the data storage).

Problem: If the registration was determined using point sets, the reference input will be a point set. Point sets have no "real" 3D geometry. So if you then use the "map" functionality, the mapper will always produce an empty image as a result.

Proposed Solution: The predicate for the reference input should only allow image based data types. Then if the autodeduction would e.g. return a point set it will be ignored.