Thank you, Chris and James, for your input. Chris, what you said about
editing things (deleting, formatting, etc.) makes perfect sense, and
confirms my assumptions. Your description of the TIP, and of how to
change text, is much less clear.

You said that one selects text, opens the TIP, and modifies the text.
So far so good, but you have only explained WHERE one modifies text
(in the TIP), not HOW.

Let's take a realistic example. Suppose I wrote "Any sale, lease, or
other transfer," and I now want to change it to, "All sales, leases,
exchanges, or other transfers." How do I do this?

If I were using "nice" editing software (with the TIP a given) I
could:

1. Select the sentence with a pen, moving it to the TIP.
2. Scratch out (or select) "Any" and replace it by writing "All."
3. Point after "sale" and write an 's'.
4. Point after "lease" and write an 's' and a comma.
5. Point after the comma and write ' exchanges' and a comma.
6. Point after "transfer" and write an 's'.
7. Reinsert the contents of the TIP in the text.

Now, doing the work this way seems to require elementary editing
gestures which you've implied do not exist. How, then, is it done? I'm
trying to imagine some design that does not force me to either delete
and rewrite the whole thing, or select, edit and reinsert each changed
word. I can think of several ways it MIGHT work, but none of them are
easy.

My email address is llm040903 at earthlink dot net.