Thanks, now I see the problem.
The files added to the “/SPJS/DSSF/Custom” folder must be referred in the JSLink setup page – in the Custom JS and CSS files (not in the Custom JS in DFFS backend):
This method will load the code in all forms using the same setup (if you use a site column).
To load a custom js file in ONE DFFS form, look at the help icon above the Custom JS textarea for a link to the $.getScript jQuery method.
Hope this helps,