It should not be possible to select "non-existing" Tiles in Collection of Images. (original) (raw)

For end users, this almost feels buggy:

I can select 3 "empty" Tile slots, where nothing is there and I can assign them with values ("xxx") like in the GIF. But obviously I'm not assigning them with values, but the very last Object (the leek in the example) is assigned. It would be less irritating for the User to not be able to select these empty slots at all.