As the title state, I think it's better not to hard code the menu item history, and use about:config so we can configure how much the history shown to us, as https://bugzilla.mozilla.org/show_bug.cgi?id=1306752 bug still isn't fixed til today... It's hardcoded to 15 item only as stated on the code.
http://searchfox.org/mozilla-release/se ... egexp=true
http://searchfox.org/mozilla-release/se ... MENU_ITEMS
Please allow common user to show the history based on their own configuration to more than 15 using about:config. alt+s is the king of history, hurrah!