Variable: gnus-use-undo
gnus-use-undo is a customizable variable defined in gnus.el.gz.
Value
t
Documentation
If non-nil, allow undoing in Gnus group mode buffers.
Source Code
;; Defined in /usr/src/emacs/lisp/gnus/gnus.el.gz
(defcustom gnus-use-undo t
"If non-nil, allow undoing in Gnus group mode buffers."
:group 'gnus-meta
:type 'boolean)