FujiFilm EF-60 Shoe Mount Flash - Manual (Page 20)

Press for 1 second at the center of
the “Control wheel and buttons” to
lock the set value. While the lock is on,
the settings and functions that can be
set with the “control wheel and
buttons” cannot be changed, and the
power does not turn off. (However, the mode can be
changed using the "mode dial.")
To unlock, press the center again for 1 second.
Operation lock button
Function Button