No dismissal, voluntary or involuntary, of a plaintiff's civil action shall operate to dismiss a previously filed counterclaim or cross-claim. No dismissal, voluntary or involuntary, of a plaintiff's civil action shall operate to discontinue any ancillary matter pending before the court. If an ancillary matter is not ruled on within ninety days after the dismissal, it is denied.
Mo. R. Civ. P. 67.05