> It’s the Google way.

Don't forget the all-important last step: abruptly killing the product - no matter how popular or praiseworthy it is (or heck: even profitable!) if unnamed Leadership figures say so; vide: killedbygoogle.com

Hmm, yes; I think you're right. I honestly don't know the explanation behind that, sorry.

I accept that's possible - if not likely (and everyone steals from each other!) - but even-so it only amounts to to the gunmetal-grey default colours and use of a 1px bevel/inset effect; because NS and NT3/NT4's UX/UI design and concepts are just so different otherwise.

...but I'm not personally convinced: instead, consider the demonstrable fact that similar engineering teams, working on similar problems, will independently come to substantially similar solutions; my favourite example to point to is how eerily-similar the Eurofighter Typhoon, Saab Gripen, and Dassault Rafale all look - even entirely indistinguishable at an air-show in-person - despite having zero shared pedigree - therefore it's possible that - given the constraints of desktop graphics hardware of the late-1980s/early-1990s - that a user-friendly desktop UI built around the concept of floating application windows - will all be similar in one way or another.

-------

My pet-theory for why that "Windows 95 1px bevel" look is so prevalent is because it suits working with premade UI graphics rasters/bitmaps using indexed-colors: for example, imagine a Windows-style Property Sheet dialog: prior to Windows 95, software would manually draw all of the elements of that dialog directly to the framebuffer (i.e. using unbuffered graphics) which was slow - ugly - and is the cmputer-equivalent of using a lavatory in a cramped bathroom actively undergoing renovations without any drywall/plastering). Even if there was enough vram for double-buffering it's still going to be slow: painting each and every button, checkbox (with the checkmark!) and tab header. So instead, many individual UI graphics elements could be prerendered (at design-time, hopefully by an actual artist), but not as single bitmaps for the entire dialog - but as an indexed color bitmap for each control type, so no slow/expensive draw/painting is required: only a simple blitbit for each checkbox, for example. Using an indexed-color bitmap based on a 4 or 8 colors palette (face, 3D light, 3D dark, transparent/BG; etc) means a single blob only a few hundred bytes in size can represent a chisel-cut bevelled checkbox - while integrating with whatever the user's preferred color scheme is.

----

....of course now we'll just build a UI in Electron, to hell with memory usage or integrating with the user's OS appearance settings. Le sigh.

> From what I remember it lost the ability to render rounded window corners,

...I'm guessing you haven't used Windows 11?

--------

By "rounded corners" are you referring to rounded-off corners in the nonclient area (such that the hWnd's rect is not clipped at all)? If so, then no: those would be rendered using a 9-grid[1] and have always been supported.

If you're referring to how so many fan/community-made msstyles for Windows 10 retain the sharp corners, I understand that's not a limitation of DWM or msstyles, just more that you need to do a lot of legwork when defining nontrivial corners in an msstyles theme; it can be done (there are plenty of examples online, e.g. look for Windows XP's style ported to Windows 10), it's just that most people don't go that far.

-----

[1] In msstyles, the 9-grid defines how a rectangular bitmap is stretched/scaled/tiled to fill a larger area; it's very similar to how CSS image borders are defined with `border-image-slice`.

The engine itself isn’t gutted - it’s full of functionality that was never lost. MS just (correctly) reasoned that transparency effects in the UI - introduced in Vista simply to show-off the capabilities of the DWM compositor - ultimately detract from a good UI.