Global menu: keyboard shortcuts (accelerators) don't work for many apps

[Dave Musicant]

When I have the global menu activated in (e.g., when using the Contemporary layout), the alt-key keyboard shortcuts for the menu don't work (alt-f for file, etc.) for many apps, including Firefox, Thunderbird, LibreOffice and others. The keyboard shortcuts work fine when not using a global menu. (I'm using version 18.04)

For some other apps, e.g. Caja, Pluma and Terminal, the keyboard shortcuts work fine.

This was further confirmed by @Bill_MI in the below conversation:

https://ubuntu-mate.community/t/global-menu-cant-get-keyboard-shortcuts-accelerators-to-work/17602

Thanks for taking a look at this.