Using dead keys acute and grave/backtick in normal mode doesn't work

Steps to reproduce

I'm using macOS with a German locale and a German keyboard where ´ (acute) is a dead key and ` (grave/backtick) is produced by hitting shift and ´.

It easier to type ´ as it does not require the shift key. Thus in my .vimrc, I have defined: nmap ´ `

This works fine in Terminal of macOS!

In MacVim, neither ´ nor ` works.

For vowels, I got it working with mappings à la:

nmap ´á `a
nmap ´Á `A
nmap `à `a
nmap `À `A

But this does not work for consonants like b. The error is raised: E78: Unknown mark

Expected behaviour

Both ´b and `b should jump to the mark.

Version of Vim and architecture

9.1.727

Environment

OS: Sequoia, arm64
Terminal: macOS Terminal
$TERM: xterm-256color
$SHELL: /bin/zsh

How MacVim was installed

Homebrew

Logs and stack traces

No response

Vim configuration where issue is reproducable

No response

Issue has been tested with given configuration

• by running MacVim.app from GUI macOS interface
• by running vim/gvim/etc installed by MacVim
• by running other versions of vim (e.g. /usr/bin/vim)

Issue has been tested with no configuration

• by running mvim --clean (or gvim, supplied by MacVim distribution)
• by running vim --clean (in terminal, supplied by MacVim distribution)
• by running vim --clean (in terminal, other suppliers, e.g. /usr/bin/vim)

Other conditions

• The both Homebrew packages "vim" and "macvim" are installed

Commencez par reproduire le problème dans MacVim.app avec mvim --clean, puis comparez-le avec vim --clean dans macOS Terminal en utilisant les mappages documentés pour l’accent aigu et l’accent grave. Suivez le traitement par MacVim de l’entrée de touche morte et des déplacements vers les marques en mode normal ; le travail est terminé lorsque ´b et `b accèdent tous deux à la marque correspondante sans E78.