Hello, first time posting. I was working with pre-keyed footage in fcpx, it's a 3D project, I don't know if that makes any difference. Anyways I got everything placed and corrected and everything squared away and thought to try to combine this project with another larger project, so I turned the clips I was working with into a compound clip so I could open them in this other project. When I did so all the pre-keyed footage became un-keyed, there were big black boxes everywhere. And when I broke up the compound clip they remained that way, completely unkeyed. Thanks for any help.