Computer Fn KEY is function key

Fn key is function key:press Fn key and press other key other function

Fn sticky function is :

StickyKeys is an accessibility feature to help computer users who have physical 

disabilities, The Sticky Keys feature allows you to use key combinations involving the Ctrl ,

Alt , or Shift key by pressing only one key at a time. 

press Fn  release ,press other key like f1 is other function continue press f1 is f1 function

double press Fn release Fn state lock???

FnLK function is lock Fn function state:

press FnLK lock fn state