Subject: Re: bug#11445: 24.0.96; Customize buffer edit fields should have undo

From: Mauro Aranda <[email-masked]>
Date: Wed, 02 Jun 2021 09:21:39 -0300

Lars Ingebrigtsen <[email-masked]> writes:

> "Drew Adams" <[email-masked]> writes:
>
>> A text editing field in Customize is like text editing in general.  Why
>> shouldn't undo be available to users here?
>
> As far as I can tell, `undo' works fine in text fields in Customize
> buffers.  Are you still seeing this problem in recent Emacs versions?

It cannot work reliably: if a widget needs to be redrawn, the widget
code will clear the undo information with widget-clear-undo.

Try this:
emacs -Q
M-x customize-group RET mouse
TAB until point is at the arrow to expand the double-click-fuzz option
RET
TAB to move to the field
deletechar
4
C-x u shows the empty field, which is fine
C-x u again: "No further undo information".  But that's not expected; if
undo worked, the field value would be the default value.