It would be the key part if it had actual information. What type of programs are "some programs"? Too many controls, multi-window, drag-and-drop, too fast contr

It would be the key part if it had actual information. What type of programs are "some programs"? Too many controls, multi-window, drag-and-drop, too fast control updates or rendering, 2D graphics, extensible controls, etc.? GUI frameworks have pretty common components, and clearly they know something about the limitations, but those limitations aren't enumerated at all.