Appeal from the Circuit Court of Kane County. No. 97-D-1022. Honorable Stephen Sullivan, Judge, Presiding.
 The opinion of the court was delivered by: Justice Gilleran Johnson
 On March 2, 1997, in British Columbia, Canada, the respondent, Anezka Bouz, f/k/a Anezka Chrobak, a/k/a Agnes Chrobak, obtained a divorce from the petitioner, Karel Chrobak, a/k/a Charles Chrobak. Subsequently, in Illinois, the petitioner petitioned for a legal separation (see 750 ILCS 5/402 (West 2002)). On November 5, 1997, the trial court granted the petitioner's petition for a legal separation and incorporated into that order the parties' settlement agreement. Five years later, the respondent petitioned to vacate the legal separation order and the incorporated settlement agreement (see 735 ILCS 5/2--1401(f) (West 2002)), arguing that the trial court lacked subject matter jurisdiction to enter the separation order because the parties were divorced. The petitioner moved to strike and dismiss the petition, claiming, among other things, that the respondent was estopped from challenging the order because she accepted the financial benefits that the settlement agreement gave her. The trial court granted the petitioner's motion to strike and dismiss, and this appeal followed. On appeal, the respondent contends that the trial court lacked subject matter jurisdiction over the proceeding for a legal separation. The petitioner claims that the respondent has waived this issue or is estopped from challenging the trial court's jurisdiction. We agree with the petitioner's estoppel argument. Thus, we affirm.
 On December 29, 1962, the parties were married in Chicago, Illinois. They lived in Kane County as a married couple for nearly 30 years and raised three children, who are now adults. In February 1992, the respondent left the petitioner and moved to Canada, where she lived previously. Five years later, the respondent petitioned for a divorce in Canada and properly notified the petitioner. The petitioner, who had no contacts with Canada, did not appear at the Canadian divorce proceedings. The parties' marriage was dissolved in Canada on March 2, 1997, but the divorce decree did not address maintenance or the division of marital property.
 On July 24, 1997, the petitioner petitioned for a legal separation in Illinois, acknowledging the Canadian divorce decree. The respondent was personally served with the petition for a legal separation, but she failed to attend any of the proceedings. At the subsequent hearing, the petitioner, who was the only witness to testify, agreed that the Canadian divorce order did not address property or support issues, which the petitioner wished to resolve with the order for a legal separation.
 In that regard, the petitioner testified about the parties' settlement agreement. He stated that he entered into the agreement freely, that the agreement was fair, and that the respondent signed the agreement. The agreement provided that the parties would sell their home and share the proceeds, which they did, and they divided the amount they had in their savings and checking accounts. The petitioner stated that the parties split the money he had in a pension, and he provided a survivor's annuity to the respondent. The petitioner also has paid the respondent maintenance since February 1992, and, pursuant to the agreement, he will continue to pay her $1,000 per month until, among other things, she remarries or starts receiving social security. The trial court found that the respondent was in default by consent or otherwise, granted the petition for a legal separation, and incorporated into the judgment the settlement agreement, which it found fair, reasonable, and not unconscionable.
 On November 6, 2002, the respondent moved to vacate the judgment for a legal separation and the incorporated settlement agreement, arguing that the judgment was void because the parties were divorced when it was entered. The respondent contended that, pursuant to comity principles, the trial court should have recognized the Canadian divorce order and thereby acknowledged that it lacked subject matter jurisdiction to grant a legal separation. The petitioner moved to strike and dismiss the petition to vacate, arguing, among other things, that the respondent should be estopped from challenging the order for a legal separation and the incorporated settlement agreement because she profited from the order when she accepted maintenance and other benefits. The trial court granted the petitioner's motion to strike and dismiss, finding, among other things, that the respondent accepted the benefits of the settlement agreement. This timely appeal followed.
 On appeal, the respondent claims that the trial court lacked subject matter jurisdiction over the legal separation proceedings because the parties were already divorced. The petitioner contends that the respondent has waived the argument or is estopped from challenging the trial court's subject matter jurisdiction.
 Before addressing these arguments, we consider our standard of review. The parties disagree about the proper standard to apply. The respondent claims that we should invoke a de novo standard of review because, among other things, the essential issue raised on appeal is whether the trial court had subject matter jurisdiction over the proceedings. See In re Marriage of Devick, 315 Ill. App. 3d 908, 912 (2000). The petitioner argues that we should employ an abuse of discretion standard because, among other things, a trial court's decision whether to recognize a foreign judgment is discretionary. See Ransom v. A.B. Dick Co., 289 Ill. App. 3d 663, 669-70 (1997). We determine that the standard of review is de novo because the issue raised is whether the trial court had subject matter jurisdiction over the legal separation proceedings. See In re Marriage of Adamson, 308 Ill. App. 3d 759, 764 (1999).
 We next address the petitioner's waiver and estoppel arguments. We will first consider the petitioner's claim that the respondent has waived challenging the trial court's lack of subject matter jurisdiction because she participated in the proceedings without objection. A judgment entered by a court that lacked subject matter jurisdiction is void and may be attacked at any time and in any proceeding. Adamson, 308 Ill. App. 3d at 764. When subject matter jurisdiction is lacking, it cannot be conferred by stipulation, consent, or waiver. Adamson, 308 Ill. App. 3d at 764; see also In re Marriage of Alush, 172 Ill. App. 3d 646, 651-52 (1988) (noting that wife could challenge trial court's jurisdiction over contempt proceedings even though wife responded to husband's petition for a rule to show cause). Given these well-established rules, we determine that the petitioner's waiver argument lacks merit.
 Before considering the petitioner's estoppel argument, we note that the special concurrence recites the test for collaterally attacking a void judgment that was delineated in the Restatement (Second) of Judgments §12 (1982). Our supreme court mentioned this test in In re Marriage of Mitchell, 181 Ill. 2d 169, 176 (1998), but specifically stated that it was not adopting that test in lieu of the traditional view, which provides that void judgments may be attacked at any time, either directly or collaterally. Mitchell, 181 Ill. 2d at 177. Because the Restatement has not been adopted by our supreme court, it is not the law, and merely provides guidance. See Ziemba v. Mierzwa, 142 Ill. 2d 42, 49 (1991). As such, we believe that the traditional view is the current law and that void judgments may be collaterally attacked.
 We now consider whether the respondent is estopped from claiming that the trial court's order for a legal separation, which incorporated the parties' settlement agreement, was void for lack of subject matter jurisdiction. In general, estoppel does not apply to void orders. Cash v. Maloney, 402 Ill. 528, 536 (1949). However, in dissolution proceedings, a party who accepts the benefits of a divorce decree may be estopped from later challenging the order even if the challenge involves a claim that the order is void because the trial court lacked subject matter jurisdiction to enter it. See In re Marriage of Yelton, 286 Ill. App. 3d 436, 442 (1997); In re Marriage of Schlam, 271 Ill. App. 3d 788, 793 (1995); In re Marriage of Monken, 255 Ill. App. 3d 1044, 1047 (1994).
 The question then becomes whether receiving maintenance and other financial benefits of a legal separation order amounts to "accepting benefits" as used in the estoppel rule. "Accepting benefits" is most often applied in cases where a party remarries in reliance on a divorce decree. See, e.g., In re Marriage of Gryka, 90 Ill. App. 3d 443, 446, 449 (1980) (noting that remarriage in reliance on valid divorce decree is accepting benefit). In those instances, the rule is frequently called "estoppel by remarriage." Schlam, 271 Ill. App. 3d at 793. History suggests, however, that application of this estoppel rule is not limited to situations where at least one of the parties remarries. For example, courts have concluded that "accepting benefits" can include accepting financial benefits of a dissolution or separation order. See, e.g., Henley v. Houck, 49 Ill. App. 2d 472, 474-76 (1964) (holding that wife, who remarried and accepted various financial benefits of divorce decree, was estopped from attacking decree's validity); Guelzo v. Guelzo, 292 Ill. App. 151, 156 (1937) (concluding that wife was estopped from vacating divorce decree on grounds that the parties cohabitated after separating because she accepted the financial benefits of parties' settlement agreement into which she and the husband entered). In fact, the court in McDonald v. Neale, 35 Ill. App. 2d 140, 143-44 (1962), which is perhaps the seminal Illinois case on this estoppel rule, held that the wife was estopped from challenging the divorce decree because, not only did she remarry 11 years after the divorce, she also accepted the proceeds of the parties' settlement agreement.
 Turning to the facts presented in this case, we hold that the respondent is estopped from attacking the legal separation order, which incorporated the parties' settlement agreement, because she benefitted from the order. Specifically, in June 1997, the respondent signed the settlement agreement, which gave her, among other things, a set amount of maintenance and a portion of the petitioner's pension with a survivor's annuity. The trial court entered the order for a legal separation on November 5, 1997, and incorporated into that order the settlement agreement. Although the respondent did not attend any of the proceedings for the legal separation, she was properly served with notice.
 Despite knowledge of the Canadian divorce order and the Illinois proceedings for a legal separation, the respondent never timely challenged the trial court's subject matter jurisdiction. She never objected to the trial court's jurisdiction over the matter during the proceedings, she did not file a posttrial motion challenging the trial court's subject matter jurisdiction within 30 days after entry of the legal separation order, and she did not appeal the legal separation order. Instead of taking any of these steps, the respondent, who has never denied that she received financial benefits of the legal separation order, waited five years after the order was entered before ...