Digital Cinema Desktop Preview - missing in FCP7 on OS X Yosemite

I am trying to use a second screen as preview monitor in FCP7. In the past I could easily select "Digital Cinema Desktop Preview" and use either the main or secondary display to preview the edit.

However, I am using FCP7 on a OS X Yosemite 10.10.5 and the option of "Digital Cinema Desktop Preview" is nowhere to be found. I have tried restarting, trashing FCP preferences, and unplugging and re-connecting my monitor.

No matter what I do, the option is unavailable. I've looked everywhere you should be able to select it. Does anyone know how to get the option back?