A similar problem I’ve ran into both in tech support and user studies is momentary blindness for the scope of search. For example on your Mac, you have Spotlight, Finder search, Google search, help menu search, and various application-specific or website-specific search fields. In my experience if two of those are on screen at the same time, it’s very easy to get confused about which one to use to get which type of r…
Other than "momentary" blindness, it feels like some people don't look at their monitors three-dimensionally: It's just buttons and fields everywhere, there's no physical separation between them, there's no hierarchy. They just learn to operate some UIs mechanically and don't put any thought into it. That's why they whine when something moves; As far as they're concerned, that something disappeared into an alternate…
I've often joked that one of the core skills of a programmer is to be able to look at a terminal scrolling a full screen of text every quarter of a second or so, and extract useful information from it. I've lost track of the times I've seen something "different" and had to scroll up dozens of screens to find what I happened to see.
This is a job-specific skill like a mechanic diagnosing a complicated machine's problem from the particular way a single knocking sound sounded, or a doctor glancing at you and telling you you have some obscure disease that you've never heard of because you have some particular droop in your eyelids. This is not the way the non-programming public perceives a computer screen.