There are two good books I can recommend regarding the design of X11 and how windowing, widget primitive, and compositing work: - X Toolkit Intrinsics Programm

There are two good books I can recommend regarding the design of X11 and how windowing, widget primitive, and compositing work: - X Toolkit Intrinsics Programming Manual - X Toolkit Intrinsics Reference Manual However they have very little to do with how modern operating systems (Windows, MacOS) deal with that stuff. As for toys, I'd recommend reading about Dear ImGui [1]. It handles everything you mentioned while being self-contained so you can see how everything works from top to bottom. Many talks and articles have been written about it though I can't vouch for any of them. 1. https://github.com/ocornut/imgui/wiki https://github.com/ocornut/imgui/wiki