Oppo 205 owners

Anyone have a problem using the test tone feature in the speaker setup. Mine not seem to be activated, I can't select the button. 
I got the answer from Oppo, I had a CD in the tray,  not playing, just left in there. That stopped the button from activating, just the test tone button. 
Who would know?
Nice to know. Thanks for looking into an odd idiosyncrasy. A.