How do i disable Fn Key on Microsoft Surface Ergonomic Keyboard for OS X? I recently acquired a MS Surface Ergonomic Keyboard. Its a great device for everything other than a Fn lock key that is awkwardly placed between the CTRL and OPTION/WINDOWS key. 

I've looked at the keyboard viewer to see what input is being communicated so i might try and override it in Karibener Elements - but the Keyboard Viewer is not showing any key inputs.

How do i find what key is being triggered and disable it? 

Note: The 'Fn' key is stateful like a caps lock key.
It seems like the keyboard handles the Fn key itself, rather than passing it through to the OS to handle. Since the OS doesn't receive the Fn key input, it can't do anything to change it.

Therefore, disabling the Fn key would have to be something the keyboard would allow you to control, either on the keyboard itself or with a tool which writes that information back. I can't find either of these, so I don't think it's possible currently.