Seems to be a bug in FCP X unless I'm doing it wrong, but 2 things re: changing the names of clips using the info tab and then selecting the gear at the bottom and applying cusom name
1. If you change the names of the clips and update them by refreshing the "apply custom name" it will change the names in the event library but NOT on your timeline if they have already been placed...so, in my case, I had to renumber a bunch of clips and then on my timeline found I had multiple clips with the same name.
2. once you've renamed your clips you can't search for them via the original name. For instance, if you can't find a particular clip and you go back to your source files, you can't copy the name of that file and, in fcpx search, find if it's been digitized. You can only search via the new name. On a big documentary project like mine, for instance, it can be a problem discovering if a clip was put into a different folder by accident. You'd have to revert clips to their original names and search from there. Seems the metadata should be searchable, but it isn't
curious if others have found this problem or have a solution