Physical objects should be rounded, virtual windows should be square. I will die on this hill.
also, where is the new version of Visual Basic, Ballmer? Your sweaty chants can only distract me for so long…. Wait….. ITS BEEN TWENTY YEARS!?!?
CRTs might have actually liked being nearly hemispherical because glass and deflection-from-center.
found the Windows 8 enthusiast! haha, I kid. (I myself use a tiling window manager , i3, with completely square windows without any gaps or rounding)
If I could run the Windows 2000 UI on a modern OS I would but any recent clone/theme/etc feels too uncanny valley.
(Yes, please tell me about some buggy half-compatible tiling window manager for my Mac.)
The square corners are part of a 2 pixel wide border (one black, one white) because who needs to waste space on handling things we aren't manipulating? But the title bar is high-contrast, because you'll go looking for it when you want to switch windows.
The round corners go with a fairly thick border in a customizable color, usually something very bright in the yellow, orange or cyan ranges. When you sit down, you should immediately know what is active.
They don't have to be any particular shape or size. The property of being virtual overrides everything else when free of these self-imposed constraints.
Even if you lose the GUI and go back to text, the ideal terminal is a plane of infinite columns of arbitrary cell size that dynamically fills your field of view.
I'd further argue that the only reason VR/AR isn't more widely adopted is the lack of orthographic vs perspective modality per application (and uncomfortable headsets). In VR/AR, you don't want a window manager or even windows at all. What you want is a field manager (as in FOV "fields" of varying opacity that can be composited by the user). Shape and size is just an arbitrary region blended in with the environment.
For the sake of ergonomics, you'd more often prefer to project an interface onto a surface if you had the choice. When you don't, you probably want the projection to be orthographic, but for the edges to be fuzzy if not invisible. You'd generally want to be able to layer these interfaces as well instead of having opaque rectangles always in your way.
This makes perfect sense considering that most LCD displays, and practically all computer displays, don't have rounded corners. This trend of rounding displays and GUI elements is purely an aesthetic choice. I also find this obnoxious since the only thing it does is rob me of a few pixels which are often useful.
But considering Apple users have accepted living without a large block of pixels dead center at the top of the screen, which they've been sold as a "feature", the rounded corners are likely even less of an issue.
I'm not sure that an infinite plane of pixels makes sense even in XR. I want to see a clear edge of where digital content begins and ends, and a rectangle is the simplest and most optimal shape for that. So I would rather have physical display-like floating rectangles, than floating text in arbitrary locations, or rounded off corners for the sake of aesthetics. I'm not opposed to a very slight rounding off of edges on certain elements, but the trend Apple is pushing is supremely ridiculous.
I'm saying that there is room for your arbitrary preference for opaque rectangles if we all abandon the notion of a "screen". We are well past the point where we can do this economically. It only persists because of consumer acceptance. Traditional screens are less efficient in every tangible way. They are less power efficient for their apparent brightness and require more material to construct.
Even the notion of clear boundaries and pixel size is an illusion. Traditional screens only make the pixels so big because they require sufficient brightness and power to see them at that distance, not because we cannot manufacture smaller pixels for cheaper. We could have much better results for everyone and the only remaining cost/problem is finding a way to comfortably wear the display.