It is a huge UI problem. For example, it's tempting to start adding flashy chrome to a structure editor just because you can. Pretty Lisp's rounded rectangles a

It is a huge UI problem. For example, it's tempting to start adding flashy chrome to a structure editor just because you can. Pretty Lisp's rounded rectangles are obviously not going to scale to real programs; they generate a lot of noise. Visually, an ideal structure editor looks a lot like the text-format code we have today for its readability. There's a lot of usability failure in Lisp's history but I know that a great structure editor is possible.