For some reason subscribing to list does not work for me, so I only saw your reply in archive ...
mgSTEP in this case surely was run on top of X11, but it can be switched compile-time to framebuffer. speaking about modern Qt - it become ... a bit massive in last 25+ years ... so I do not thinking anything lighter will be "competing" with it Perhaps i should put it on github, so internals will easier to discuss Also, I was surprised someone did GUI/window (one window) demo in Forth! https://github.com/gopalkrishnareddy/awesome-iOS-resource/blob/master/Books/Mac%20Os%20X%20Internals%20-%20A%20Systems%20Approach.pdf "Figure 415 shows a rudimentary implementation in Open Firmware of a window that can be dragged.[15]"
