RE: Customize buffer modification: indicator, feedback, undo

[Drew Adams]

    emacs -Q
    M-x customize-face font-lock-comment-face

    1. Buffer *Customize Face: Font Lock Comment Face* shows "**" in the
       mode line, as if the user had already modified something in the
       buffer.

    2. Trying to type in the header text has no effect. There should be a
       message indicating that that area of text is read-only. Otherwise,
       with no feedback, the user doesn't understand what's happening and
       why.

    3. There seems to be no undo in Customize buffers. Why? Users should
       be able to undo edits at least.  Also, when you try `undo', the
       message says that no *further* undo information is available. This
       message is misleading. If undo is not available, the message should
       say so.

Correction to #3: Some editable fields (e.g. text) appear to be undoable,
but others, such as toggles, are not. Why not all - if you can edit (change)
something, then you ought to be able to undo it. If you make several changes
to, say, a face, then you ought to be able to undo them one by one.
Currently, it looks like you can only undo text areas (or revert to the
unmodified value).