Heirs of Hinog vs. Melicor, G.R. No. 140954: After recognizing the jurisdiction of the trial court by seeking affirmative relief in their motion to serve supplemental pleading upon private respondents, petitioners are effectively barred by estoppel from challenging the trial court’s jurisdiction. If a party invokes the jurisdiction of a court, he cannot thereafter challenge the court’s jurisdiction in the same case. To rule otherwise would amount to speculating on the fortune of litigation, which is against the policy of the Court.
