When I enter "Cdim7"...it corrects to "Cdim"

The chord I want is Cdim7 (1,b3,b5,6 - C,Eb,Gb,A)

Is this chord not possible in Real Tracks?

Thanks!

They're there. You have to enable the various options in the Chord Builder to find them.

Not in fromt of my Mac at the moment but, if you enter dim7 in the search box of the Manual, you'll see how to find them.