Mystery Object

In the attached file, I have an object that I can see but I cannot select. How do I correct this?
Mystery.3dm (173.5 KB)

Either unlock Selected objects command or Option+click on your lock Icon …

MysterySolved.3dm (179.6 KB)

Thanks, new feature to me. The mystery is how it got locked in the first place.

Can’t solve that one, glad to help!