Does Blackbox use any X toolkit/widget set?
No. It uses basic X functions and contains a very simple internal “toolkit” which is used to draw everything on the fly. This means that window decorations, buttons, the menu, the toolbar, slit and everything else is drawn like this, “manually”, so to speak. It also has a caching system to avoid drawing identical things each time. The only things that are “predefined” to some extent are the bitmap icons for the buttons, which are hardcoded XBM’s* (C arrays, basically) and are rendered using X ready-made functions.
