I would like to see the option in an SDB to set it so that the last item in the box cannot be sold. That way I could put the music blocks I have for sale on my ground floor in with my music blocks in my Music Room without my display being destroyed if someone buys the last one. Likewise for my cubimal display, or artifacts, if I get multiples of the same pieces - I am always going to want to hold onto one until I have completed the set, but being able to sell the excess pieces from the same SDB that I am holding the artifact piece in that I need, would be nice.