It was my duty to finish the curio shelf project and it turned out fine. A decision to hang it like a framed picture stabilized it: I punched two holes in the top, strung cord through and knotted the ends, then hung it from a nail in the wall. The weight of the contents also stabilized it. Two wooden cigar boxes just happened to fit underneath.
What keeps my goodies from falling out is a clear band of plastic sheeting which acts as a fence. I went crazy and made three more for my nephew and two nieces. Now...back to work on inventory!!