Other threads on here have mentioned issues with newer versions of gamemaker, and I notice the downloads include some extra files labelled as being for GM 8.1 0 (I am using  v2024.8.1.2218). I did not know what to do with these and so I didn't use them, and the plugin seems to work by importing the 2.3+ yymps file. Our project has however started to have an intermittent NaN bug that is hard to track down. The issue may not be related to this plugin at all, but it was one of relatively few changes we introduced lately before this NaN bug started popping up and we're having trouble figuring out where  the NaN is coming from so I figured I'd ask if that sounds familiar and if there was something I was supposed to do with the GM8.1 files.

I have a guide for GM8.1 extensions.

If you added the files and mouse lock works, you probably did it right.

I had a NaN crash once when I gave GM8.1 a C++ function that returns nothing, but this extension’s functions all return a double that is either an integer or a BOOL (also an integer).