Check it out:
MX 2004. I created a movie clip. I then grabbed it and attempted to nest it in an other movie clip.
Original movie clip remains on stage with old instance. New movie clip appears in Library, but empty. Original movie clip cannot be moved or deleted. If deletion is attempted, either from the stage or from the library, MX crashes and shuts down.
WTF! I need some serious advice. I’m nearing the end of a VERY long, very large Flash project and this hits.