Hi, 

I still can not understand, how and why the Portfolio Page item is different from a normal Page? Your documentation doesn't give a clue. It should be very expalantory, so that your grandmother would understand how a setup of a website with your theme work. Or is your documentation aimed only on experienced WP users?

To the issue:

Just tried to link a Portfolio Page item to the menu, but no such items are listed in the Menus setup section!
Wanted to look how your Architecture Project (Demo) is linked to the menu, it turnes out, you have linked in a strange and *not at all obvious* and *not in the documentation explained* structure:
Portfolios (PAGE) > ... > Architecture & Interior (CUSTOM LINK) > Architecture Project (Portfolio Item)

So what gives?
How a user is supposed to know what to do with the Portfolio Page Item, if you explicitly tell them: "Portfolio Page
This is a custom single post for describing / showing your project, case study, product etc. It works like a page: ...", but not explain how Portfolio Page items are to handle and that they behave differently than a normal page?! 
I have seen huge issues both during the Menu setup and Vertical Slider page setup, as described in my other ticket.

Attachement: I don't think I have set up the Portfolio Page item somehow incorrectly. Neither "CG" nor "CG Page" appear in the Menus setup section!

Cheers