Prefereces option is hidden in Firefox on Linux Rated 4 out of 5 stars
I am on Linux and it shows Preferences/Option in Edit menu in normal menu. So I don't see it if I enable this add-on.
In addition, are you planning to allow more customization to be allowed with this addon.
Thanks for your bug report!
Version 188.8.131.52 should work for you, avaiable through the versions menu (https://addons.mozilla.org/de/firefox/addon/new-old-menu/versions/) until the official review is done. I wasn't aware that UI changes between OS. I assume that on Mac OSX it isn't avaiable either, as far as I can see that without using it. Let me know if 184.108.40.206 worked for you!
I don't have plans to add more customization, cause there is already an AddOn that gives you the ability to customize the menu freely: Personal Menu (https://addons.mozilla.org/de/firefox/addon/personal-menu/).