Editing of invisible text

[Lennart Borgman]

Emacs lets you edit invisible text. That is perhaps not bad, but it is
bad that you can't see what you are doing when you are editing
invisible text. Here is a suggestion on how to make this better:

- Implement a minor mode that make all invisible text visible but with
a special face (or background color) that tells the user this is
really invisible text.

- Ask the user if she/he want to turn on this minor mode for the
buffer when invisible text is going to be changed.

- Of course add a variable to override this behaviour when needed ;-)