This is an extremely complex topic that has gone on for many years. One of the first and well known cases is Apple v. Microsoft and Hewlett-Packard.. in Which Apple had given Microsoft limited rights to the Mac GUI IP for Windows 1. When WIndows 2 came out, the agreement did not cover it and the user interface was so strikingly similar to the Mac GUI that Apple sued... However, Apple themselves were already in agreement with Xerox PARC for GUI concepts and that agreement did not allow Apple to license off to MIcrosoft.. this lead to Xerox PARC sueing Apple.. So we have 4 companies in a lawsuit battle over the GUI and "look and feel" of software.
At the time, no one knew if the GUI and even the look and feel of it could be copyrightable.. it was an entirely new thing, After about 3 years the judge finally came down with a decision that implementations of source code could be copyrighted, features, however, could not be. The GUI itself could be copyrighted if and only if it was unique to a certain threshold and if there were more ways in doing a specific job. For example, Apple did not win on the basis of the actual Windowing systems as the judge could not come up with another way of doing it.. it could not be considered a unique approach as it was seen as the only one. On the other hand, Apple won on the Trash can.. which is why you see a Recycle bin on Windows. Overall, Apple loss the case.. only winning a small share such as a menu bar on the top of the screen (The menu bar was actually invented at Apple in 1979).
Apple would later try to appeal, and in 1994 they began a new lawsuit, Apple v. Microsoft after pirated Quicktime hardware acceleration source code was found in Windows 95's DCI framework. Apple added this to the GUI disputes and had planned to aim for $3 billion dollars in damages. Steve Jobs however came back as an advisor to Apple in late 1996 and made Apple settle with Microsoft under a 5 year deal to stop the feud.
So it mostly comes down to: ideas are not copyrightable, unique implementations or expressions of the ideas are copyrightable... however, if it is not unique in the sense that there is only one way of doing something then it cannot be copyrighted. Unique in the sense that it is just one of the approaches in implementing a specific idea, only possible if there is more than one way to implement it.
From my experience with Photoshop, I can't see them necessarily able to get the entire GUI design copyrightable, but it is possible. At the same time, I'm not sure about the legal issues of allowing someone to use it for such a thing as video tutorials... at least if you put in credits the names and companies that developed the product.