From 2368fc6ff0d30dfee83def9e24b20b7516ef2b51 Mon Sep 17 00:00:00 2001 From: "Richard M. Stallman" Date: Wed, 17 Jan 1996 17:23:41 +0000 Subject: [PATCH] Explain avoiding x-popup-menu for menu bar submenu. --- lispref/frames.texi | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) diff --git a/lispref/frames.texi b/lispref/frames.texi index dd0b451aa8a..377e4fef98f 100644 --- a/lispref/frames.texi +++ b/lispref/frames.texi @@ -1032,15 +1032,26 @@ Each @var{line} should be a string, and each @var{item} should be the value to return if that @var{line} is chosen. @end defun -@strong{Usage note:} Don't use @code{x-popup-menu} to display a menu if + @strong{Usage note:} Don't use @code{x-popup-menu} to display a menu if a prefix key with a menu keymap would do the job. If you use a menu keymap to implement a menu, @kbd{C-h c} and @kbd{C-h a} can see the individual items in that menu and provide help for them. If instead you implement the menu by defining a command that calls @code{x-popup-menu}, the help facilities cannot know what happens inside that command, so -they cannot give any help for the menu's items. This is the reason why -all the menu bar items are normally implemented with menu keymaps -(@pxref{Menu Keymaps}). +they cannot give any help for the menu's items. + + The menu bar mechanism, which lets you switch between submenus by +moving the mouse, cannot look within the definition of a command to see +that it calls @code{x-popup-menu}. Therefore, if you try to implement a +submenu using @code{x-popup-menu}, it cannot work with the menu bar in +an integrated fashion. This is why all menu bar submenus are +implemented with menu keymaps within the parent menu, and never with +@code{x-popup-menu}. @xref{Menu Bar}, + + If you want a menu bar submenu to have contents that vary, you should +still use a menu keymap to implement it. To make the contents vary, add +a hook function to @code{menu-bar-update-hook} to update the contents of +the menu keymap as necessary. @node Dialog Boxes @section Dialog Boxes -- 2.39.2