PER CURIAM.
We affirm the jury verdict and resulting judgment of no actionable negligence on the part of the appellee/defendant below. A concurring cause instruction is not required where the only issue on the question of liability is the comparative negligence of the plaintiff and defendant, and no extraneous concurring cause is either alleged or proved.
SCHEB, A.C.J., and CAMPBELL and FRANK, JJ., concur.