The UI is a watered-down version of OS/2 (see screenshots[1]), which Microsoft was working on earlier in collaboration with IBM. And most of the "classic interf

The UI is a watered-down version of OS/2 (see screenshots[1]), which Microsoft was working on earlier in collaboration with IBM. And most of the "classic interface" we know today (in Windows, GTK+, Qt, etc.) was specified much earlier by IBM in their Common User Access[2] standard. They did come up with the start menu and taskbar, though, I think. Which was then copied by OS/2, GNOME, KDE, Xfce and others. And ruined in subsequent Windows versions. [1] https://guidebookgallery.org/screenshots/os221 https://guidebookgallery.org/screenshots/os221 [2] https://en.wikipedia.org/wiki/IBM_Common_User_Access https://en.wikipedia.org/wiki/IBM_Common_User_Access