Shotwell is very usefull, even to manage scanned photos.
These scanned photos are only tagged with the date of the scan process (file creation date). So, after the import in Shotwell, they are dispatched everywhere and it is difficult to retrieve them to manually put the right date according with the subject/content of the picture.
It could be useful to have a tick box (by example) in the F4 function panel, so after the import we could force “No event” so it could be easy to retrieve photo that are waiting for a manual event.
It could simply delete dates from iptc, xmp, exif and keep only the file dates.