Experimental Windows XP theme aped Mac's Aqua user interface
A recent source code leak reveals Microsoft built and tested a number of divergent themes for Windows XP, with one closely resembling Apple's legendary Aqua GUI.

Among a cache of Windows XP source code files that leaked online Friday are a variety of unused, sometimes incomplete, UI themes Microsoft created for its early 2000s operating system, reports The Verge.
One theme, dubbed "Candy," will be very familiar to anyone who has used a Mac running Mac OS X 10.0. A number of UI elements closely resemble or match Apple's Aqua theme, a fact perhaps most apparent in shiny, rounded window buttons designed to mimic droplets of water.
Aqua debuted at the Macworld Conference & Expo in 2000 and made its way onto Mac a year later. The theme uses a unique combination of depth through shadows, bright colors, translucency, rounded interactive assets and textures to create the appearance of liquid or gel sitting on metal plates.
According to The Verge, "Candy" was present in early source code for Windows XP, with developers using the skin as a placeholder as they built out the operating system's theme engine. Files refer to the theme as a "Whistler skin with eye candy," and are marked as "for internal use only," the report says. Microsoft referred to Windows XP as "Whistler" prior to its market debut.
The Redmond, Wash., software giant ultimately landed on a blue, green and silver theme called Luna. While it incorporated shadows and gradients to indicate depth, Luna lacked the translucency that Aqua provided, making it more akin to traditional Windows versions.
Apple and Microsoft have for decades battled in the desktop operating system space, with each company looking to outdo the other on features, capabilities and style with every new release. As the most prominent user-facing element, themes were often viewed as a key differentiator. In recent years, however, the focus has turned to more functional aspects like reliability, security and performance.

Among a cache of Windows XP source code files that leaked online Friday are a variety of unused, sometimes incomplete, UI themes Microsoft created for its early 2000s operating system, reports The Verge.
One theme, dubbed "Candy," will be very familiar to anyone who has used a Mac running Mac OS X 10.0. A number of UI elements closely resemble or match Apple's Aqua theme, a fact perhaps most apparent in shiny, rounded window buttons designed to mimic droplets of water.
Aqua debuted at the Macworld Conference & Expo in 2000 and made its way onto Mac a year later. The theme uses a unique combination of depth through shadows, bright colors, translucency, rounded interactive assets and textures to create the appearance of liquid or gel sitting on metal plates.
According to The Verge, "Candy" was present in early source code for Windows XP, with developers using the skin as a placeholder as they built out the operating system's theme engine. Files refer to the theme as a "Whistler skin with eye candy," and are marked as "for internal use only," the report says. Microsoft referred to Windows XP as "Whistler" prior to its market debut.
The Redmond, Wash., software giant ultimately landed on a blue, green and silver theme called Luna. While it incorporated shadows and gradients to indicate depth, Luna lacked the translucency that Aqua provided, making it more akin to traditional Windows versions.
Apple and Microsoft have for decades battled in the desktop operating system space, with each company looking to outdo the other on features, capabilities and style with every new release. As the most prominent user-facing element, themes were often viewed as a key differentiator. In recent years, however, the focus has turned to more functional aspects like reliability, security and performance.
Comments
And then Apple turned the UI into flat and ugly.
The important thing to remember here is that there is a big difference between "look & feel" and "user experience" or UX. Copying some aspects of Apple's "look & feel" on top of the Windows operating system, be it Windows XP or Windows 10, will never transform Windows OS into macOS, period. The behavioral aspects of an OS, things the OS does to hide/abstract the underlying OS complexity from the user, the consistency of workflows across user interactions in the OS, default behaviors, and how the OS accommodates varying levels of user, etc., are just a few of very many things that go well beyond defining an operating systems UX as opposed to its "look & feel."
A great way to experience the delta between "look & feel" and UX is to try the "Twister OS" on your Raspberry Pi 4. It's an impressive implementation of Windows 10 or macOS "look & feel" that runs on a Raspberry Pi 4. In the Windows 10 version they even provide an x86 emulator to run some x86 code on the Raspberry Pi ARM chip. It's an impressive implementation, but in no way does the UX come close to what you get with the operating systems that it is copying from a "look & feel" standpoint. It provides the UX of the underlying operating system, Raspberry Pi OS (Raspbian) with a Windows 10 (or macOS) skin. I have only tried the Windows 10 version.
It's kind of like people who wear the uniform shirt of their favorite athlete. If you're doing it to pay homage or advertise your support of the player, that's one thing. If putting on the shirt makes you think you can take the field and perform at the same level as the professional athlete, you're in serious trouble. So thank you Microsoft for paying homage to Mac OS by trying on the Aqua shirt, but be very careful with what you try do while wearing it so as not to embarrass or injure yourself.
Here's a news flash. Apple didn't come up with the idea of the personal computer, graphical user interface, portable music player, printer, monitor, laptop, smartphone, smart speaker, tablet, wireless charging, bluetooth ear buds, or smart watch. All of these things existed long before Apple decided to create their own embodiment.
Microsoft engineers come out with tons of great ideas. They are held back by:
1. management - though this has become much less of a problem under Nadella than in previous eras
2. business needs (such as backwards compatibility)
What Microsoft is trying to do is use the cloud to help them overcome both barriers.