https://github.com/ocornut/imgui
https://github.com/ocornut/imgui/wiki/Links
Maybe It is better than nimx, Perhaps nim can add it.
And I have try iup and gtk before, I think they are cross platform Inconvenient to use, Must use x11 and nonfluency on macosx.
Yes, Html5 UI is good for any platform dev app, But don't know which html ui lib is good.
imgui is good for game and graphics app, It's too small.