hasChildrenAimed() {
        const target = this.target;
        if (target && (target.isAimed() || target.hasChildrenAimed())) return true;
        for (let i = 0, len = this.childrenTargets.length; i < len; ++i) {
          if (this.childrenTargets[i].isAimed() || this.childrenTargets[i].hasChildrenAimed()) return true;