I have read through folklore.org but I never noticed that change in UI from 1979 to 1980. Thank you for pointing that out. Now that I am paying attention to th

I have read through folklore.org but I never noticed that change in UI from 1979 to 1980. Thank you for pointing that out. Now that I am paying attention to that, I see in Jan. 1980 Raskin wrote "A lightpen for graphic input is being considered" for the Macintosh. http://web.stanford.edu/dept/SUL/sites/mac/primary/docs/bom/jan80.html http://web.stanford.edu/dept/SUL/sites/mac/primary/docs/bom/... . In the link you pointed to shows that by summer of '80 there was no longer support for softkeys and there was support for a mouse. The primary documents at http://web.stanford.edu/dept/SUL/sites/mac/mouse0.html http://web.stanford.edu/dept/SUL/sites/mac/mouse0.html only start talking about a Macintosh mouse in spring of '80. This fits well with a transition from Canon Cat UI to a PARC-derived UI, as you've described.