The detent cap is probably worn out or sticking, its easily replaced.
You should not have to worry about losing the spring or detent balls as they are firmly attached to each piece. (rScotty might be thinking of a different style detent used in some rear remote setups).
The new detent cap is part number XCAP210725, or 36001-0043 both the same part, except the first number is made by Walvoil, the second number is a Korean copy.