As a fan of FCPX I was very disappointed when I found this bug/design flaw. In many workflows involving compound clips, media management becomes a disaster. I’m posting this so it gets attention – hoping this gets fixed ASAP.
*UPDATE* I’ve just received word that Apple is aware of this as a known issue. Also, there is a comprehensive thread here about it on Creative COW. I’ll keep this up here as a resource to others who stumble across the issue in the meantime.