Variable: buffers-menu-max-size
buffers-menu-max-size is a customizable variable defined in
menu-bar.el.gz.
Value
10
Documentation
Maximum number of entries which may appear on the Buffers menu.
If this is 10, then only the ten most-recently-selected buffers are shown. If this is nil, then all buffers are shown. A large number or nil slows down menu responsiveness.
Source Code
;; Defined in /usr/src/emacs/lisp/menu-bar.el.gz
;;; Buffers Menu
(defcustom buffers-menu-max-size 10
"Maximum number of entries which may appear on the Buffers menu.
If this is 10, then only the ten most-recently-selected buffers are shown.
If this is nil, then all buffers are shown.
A large number or nil slows down menu responsiveness."
:type '(choice integer
(const :tag "All" nil))
:group 'menu)