When a proceeding under this chapter involves the determination of an issue of fact, or a mixed issue of law and fact, such issue may be tried in the court in which the proceeding is pending and determined in the same manner as issues of fact and mixed issues of law and fact are tried and determined in other civil actions, with the right to trial by jury preserved to the parties, on any issue as to which such right would have existed in an action for affirmative relief. (Amended 1963, No. 176, § 1; 1971, No. 185 (Adj. Sess.), § 130, eff. March 29, 1972.)