content: Well, Gnome/xfce .etc are all Desktop Environments, they alter how the system looks, and how you interact with it on the surface, they are an interface, nothing more. ReactOS isn't a DE, it's an entire operating system. It's not linux at all, because it does not use the linux kernal (the central piece of code that determines how the OS interacts with filesystems and hardware and whatnot), it uses a custom kernal built to be very similar to the windows NT kernal in an attempt to make NT programs natively compatible. In a sense, lets say an operating system is a car. the Kernal is the car's chassis: everything is built on top of it, the distribution (in linux's case,things like fedora, debian, arch .etc, in window's case xp/vista/7/8/10) is the engine, its built ontop of the chassis, and all engines that fit on the same chassis have to be pretty similar- a smart car's chassis isn't going to fit the engine of a semitruck, but they don't have to be identical, and then the Desktop Enviornment, along with other programs, is the car's body and color. There's some basic level of intercompatibility here- while I can't put the body of a minivan onto the engine and frame of a smartcar (trying to put the win 7 UI onto fedora, for instance), but I can put a Pickup or an Suvs body on the same frame, because they are pretty similar (putting XFCE onto Fedora, despite the fact that it defaults to Gnome). ReactOS is trying to recreate a Chassis that can fit programs that were designed for windows without altering the programs, despite putting a different engine on, and not being allowed to see the blueprints of the original chassis (windows NT)