After the case was finally lodged in the circuit court for a trial de novo, appellants filed, for the first time, an answer and a Count II pleading denominated as a “counterclaim” on August 16, 1983. By the counterclaim pleading, appellants sought a diminution in the value of the leasehold resulting from respondent’s alleged failure to provide heating and air conditioning to the apartment, a theory of breach of an implied warrant of habitability. The trial court expressed some concern about its jurisdiction over the matter because it had not been pleaded in the associate circuit court. No objection was ever made by respondent to the filing of the counterclaim, and since the trial court had subject matter jurisdiction over the issue, the late filing must be considered to have been waived. The trial court did not rule the case on any failure of appellants to plead the counterclaim first in associate circuit court as required by § 512.290, RSMo [amended by L.1978, p. 696, § A (§ 1), eff. Jan. 2, 1979], but proceeded to rule the issue of breach of the implied warranty of habitability.