Tkinter: Missing the last piece of the puzzle

[MartinRinehart at gmail.com]

I have a simple editor built into my visual parser. It has a File menu
with
typical New, Open, Save, Save As ... options. I now know how to set
the options [en/dis]abled and how to check the Text widget's modified
flag.

Now I want to [en/dis]able those options. Can I ask the text to notify
me when the modified flag changes? Can I set the statuses when the
user clicks File, before the options are displayed? Do I need to
create
a checker on an independent thread that looks at the flag every few
millis?

(Tkinter deserves more respect. I've got a good-looking application
growing quickly.)