Said rule is to be strictly construed and applied. Newcomb v. Roarty, Fla. 1957, 93 So.2d 373. Incidental questions occurring throughout the litigation, the resolution of which might be helpful, if not dispositive of the entire case, are not properly the subject of a certified question. Newcomb v. Roarty, supra; Gordon v. Norris, Fla. 1956, 90 So.2d 914.