[ziml77]

I find that horizontal space to many times be more constrained. If I toss and IDE and browser window side-by-side so I can code while looking at docs I need to at least close the vertical tabs on my browser to have a sane amount of space left for content. Usually also collapse one of the sidebars in the IDE to get a decent width for the code.

[read_if_gay_]

Clearly horizontal space is going to be more constrained than vertical space if you put two windows next to each other horizontally, as you're going from 16:9 to 8:9. But if you stacked them vertically, well obviously vertical space would be even more constrained than that, to the point where it's so useless you don't even think about doing it. So this is an argument for vertical space being more scarce than horizontal space actually.

[michaelmrose]

Maybe all non page UI ought to auto hide until a key is pressed for your use case.