Okay, so it doesn't work in the Demo, even with the updated Plugin, (and no other plugin around to obstruct it) nothing happens when pressing the Buttons assigned, which leads me to believe that it is incompatibility with the controller. (if anything)
I also added the code that you posted, I pasted it at the very end of the Dungeontools Plugin file, and I must be doing something wrong, if I type in nothing, the console doesn't give out information, (which I assume is normal) but if I type in "Gamepad" like in the second picture, it just says "native code" unfortunately nothing more than that, but I used the command that was added with the string that you posted, and it just says this:
I guess I must have done something wrong or misunderstood, not sure. I tried clicking the arrow and nothing happens in every case.