I made one on fah that was a replica of the one that is built in graal except you could change every single aspect it even set a flag subject to its level and placement but it was like zco instead of co flags
It used a showimg for showing what contents poped out though but still had same everything it could however be set that once a person opened it others couldnt or that everyone could open it once.
I like yours too though i havent tested it but the way it looks it seems stable