Renaming layers in mocha for FCP

Is this a bug? I’m having trouble renaming layer in mocha for fc version 2

thanks for replying. what I found, strangely enough, was that when when I changed the preferences from dark to light, the ability to rename files was enabled. It may be possible that the ability to rename layers was enabled because of a system restart. I’m not sure but it is working now.
Thanks
Jon Grace