Q: Does PDF Studio support the top-level menu, called the Unity Global Menu, of Ubuntu?

A:  Yes, it can but you will need to install Jayatana which will automatically put the menu at the top for PDF Studio

To install Jayatana, open a Linux terminal and type in the following commands:

sudo add-apt-repository ppa:danjaredg/jayatana
sudo apt-get update
sudo apt-get install jayatana

Then log out and log back into Ubuntu.

Read more about this at this link:
http://www.webupd8.org/2014/02/get-unity-global-menu-hud-support-for.html