Greasemonkey does not work on Firefox

[coryshaw1]

The @run-at header of the userscript file just does not want to work with Greasemonkey on Firefox. Tampermonkey on Firefox works fine.

If you're having issues with this now, please use TamperMonkey for the time being!

[Exagone313]

By changing the @run-at to document-start, in console it says ReferenceError: CEnemy is not defined.
Tampermonkey is proprietary, unlike GreaseMonkey...

EDIT: This is because, at document-start, no other script is loaded, so the CEnemy function is not yet created.

EDIT2: I added a (dirty) setTimeout around the global function, to wait for the load, and now when the function loads I get:

Error: Permission denied to access object
pixi.min.js:16:16031
t/this._tick
https://steamcommunity-a.akamaihd.net/public/javascript/saliengame/pixi/pixi.min.js:16:16031

Too bad I don't have a backtrace in Firefox dev tools...

EDIT3: I copied the whole script in the console, and it works unless it reloads!