(kbd "C-c C-`") gets bound to js3-next-error, but that overrides the binding for the next match when there is a grep buffer open. Can you put js3-next-error under a different keybinding?
You can now set the custom js3-dont-rebind-backtick t to stop js3-mode from binding that to js3-next-error. In either case, if you already have something bound to next-error, js3-next-error will also be bound to that.
closed by 2a1c33a