🚀 go-pugleaf

The Lisp Machine has windows.  They can be of arbitrary width and
height, in pixels, and can be moved around and reshaped completely
dynamically.  They can have borders and labels.  Right now, as I type to
you, my screen consists of a Zmail "frame", which is split into four
"panes" (sub-windows): a big one at the top containing your original
message, a little one below that containing the "To:" and "Subject:"
lines for this message, a big one below that in which I am editing this
message (with an editor of full Emacs capability), and a little status
and prompt one at the bottom.

We use windows for all the things you mentioned.  We also extensively
use menus, some of which reside permanently in a containing window, and
some of which pop up dynamically as needed.  There are many other
related facilities which would take too long to discuss.  The window
system has been developed here over the course of several years; a great
deal of effort has gone into it.  The answer to your question is that
they are extremely useful and convenient and make everything a lot
easier to do.  Whenever I return to PDP-10 time sharing systems I
am always frustrated by the lack of a window system.

(Also, in reply to FJW: While it is true that sometimes a product ends
up making a bigger splash in an unexpected market than the one it was
targeted for, I belive that the OI market is really much bigger than the
personal program development system market.  There are lots more
managers and clerks and secretaries than there are computer experts.  So
I still think Xerox will be much more interested in OI software
development than in releasing Mesa and such.)