This Extension was a previous favorite for making Firefox usable in Microsoft® Windows® 6-up, which hid the menubars by default; the app-dropdown menu could be tailored for specific installations. I previously used this Extension with the Sparky Bluefang Extension Status-4-Evar and had no problems; this combination should still work in Ubuntu® 14.04.5-LTS, 16.04.1-LTS, 16,10, and 16.12a1 (which force single-process due to a dependency on the Package xul-ext-ubufox 3.2, an OS-specific issue).
However, the mainstreaming of multiprocess with FF 50.0.* has complicated coding matters. And with all due respect to rcmero, this Extension and the Aris Extension Classic Theme Restorer have serious mutual conflict. Recommend a beta release of a multiprocess-ready coding this Extension for field-testing in the e10s environment. (The functions this Extension cannot be replicated in WebExtensions.)