Hi there,
Yes, it helps a lot. I see it changes the perspective. They show a way to create a whole new widget, such as category pkg does, which in fact is a better approach (modular, easy to reuse and etc.)
I'm also getting back to old documentation about ad_form, plus grabbing some samples of code from classic packages such as bug-tracker, calendar, and of course, acs-subsite.
Thanks again Antonio.
https://openacs.org/file/493854/ad_form%20cheat%20sheet.pdf