X-editable bootstrap loads forever even with 200 -

i'm using x-editable bootstrap : http://vitalets.github.io/x-editable/docs.html

the docs said : if value valid, should return http status 200 ok. element on page updated automatically. no response body required.

and backend rails 3.0.20. controller (on logs), shows returned : completed 200 ok in ... ms

but... x-editable not update element on page , what's going on here ???