OPINION
BEA ANN SMITH, Justice.The State of Texas filed a petition for a writ of mandamus with this Court contending that the district court issued a void order assessing attorneys’ fees in a case after this Court’s mandate had issued. Because we hold that the trial court had jurisdiction over the parties and the subject matter at issue, we deny the petition.
BACKGROUND
The State’s petition arises out of proceedings in the district court following the issuance of our mandate in Anderson Courier Service v. State of Texas, 104 S.W.3d 121 (Tex.App.-Austin, March 6, 2003). In Anderson, we considered the constitutionality of a statute prohibiting the use of accident reports generated by the Texas Department of Public Safety or other governmental agencies for pecuniary gain. Id. at 123. Businesses that were engaged in collecting and selling accident reports, reviewing accident reports, or using those reports for solicitation purposes (whom we will collectively refer to as “Anderson Courier”) brought suit under the declaratory judgment act seeking a declaration that the statute is unconstitutional, an injunction restraining enforcement of the statute, and attorneys’ fees. Id. at 122-23. The district court found in favor of the State, upheld the constitutionality of the statute, and denied Anderson Courier’s request for attorneys’ fees. Id. at 123. Anderson Courier appealed to this Court contending that the district court erred by upholding the statute and by denying the requested temporary injunction; they sought a remand to the district court for further proceedings. Anderson Courier did not raise the denial of their request for attorneys’ fees as an issue on appeal. This Court agreed with Anderson Courier that the statute unconstitutionally regulated commercial speech; we reversed the district court’s judgment and rendered judgment. Id. at 126. Our mandate specifically reversed and rendered judgment and further ordered that “appellees pay all costs relating to this appeal, both in this Court and the court below.” An attached bill of costs itemized the fees paid to the clerk’s office and the cost of the reporter’s and clerk’s records.
After the State’s petition for review was denied by the supreme court, Anderson Courier filed a motion in the district court seeking attorneys’ fees. This motion was later incorporated into a motion for supplemental relief pursuant to section 37.011 *205of the declaratory judgment act which also sought a permanent injunction against the enforcement of the statute. The State filed a plea to the jurisdiction contending that the district court lacked jurisdiction to enter an award of attorneys’ fees. The district court denied the plea to the jurisdiction holding that Anderson Courier was
not prohibited by the Mandate issued in this cause from seeking supplemental relief as authorized by Section 37.011 of the Texas Declaratory Judgment Act; provided, however, that the Court reserves ruling on whether such supplemental relief can or should include an award of attorneys’ fees.
While litigation over the issue of attorneys’ fees continued, Anderson Courier reached an agreement in which the Travis County Attorney agreed to permanently refrain from enforcing the statute and Anderson Courier agreed not to seek attorneys’ fees from Travis County or the Travis County Attorney. The suit against the State remained, and the district court ultimately held that attorneys’ fees were appropriate and awarded $368,857 in attorneys’ fees at the trial level, plus interest, to Anderson Courier pursuant to sections 37.009 and 37.011 of the declaratory judgment act. The State filed both a notice of appeal from the district court’s judgment and this petition for a writ of mandamus.
DISCUSSION
The issue raised in this petition is limited to the question of the district court’s jurisdiction to consider Anderson Courier’s request for attorneys’ fees after this Court had rendered judgment and issued its mandate. So long as the district court had jurisdiction, the district court’s order is not void, the question of attorneys’ fees is appropriately heard on appeal, and the petition should be denied.1
Mandamus is proper if a trial court issues an order beyond its jurisdiction. In re Southwestern Bell Tel. Co., 35 S.W.3d 602, 605 (Tex.2000). We recently explained that “when a trial court exceeds its jurisdiction in issuing an order, the order is void, the relator need not show that he had no adequate remedy by appeal, and mandamus relief is appropriate.” In re Velte, 140 S.W.3d 709, 712 (Tex.App.-Austin 2004, orig. proceeding).
“Jurisdiction refers to a court’s authority to adjudicate a case.” Reiss v. Reiss, 118 S.W.3d 439, 443 (Tex.2003); Dubai Petroleum Co. v. Kazi, 12 S.W.3d 71, 75 (Tex.2000). So long as the court entering a judgment has jurisdiction of the parties and the subject matter and does not act outside its capacity as a court, the judgment is not void. Reiss, 118 S.W.3d at 443; Mapco, Inc. v. Forrest, 795 S.W.2d 700, 703 (Tex.1990). “A court’s action contrary to a statute or statutory equivalent” that does not involve jurisdiction merely renders the judgment voidable so that it may be “corrected through the ordinary appellate process or other proper proceedings.” Reiss, 118 S.W.3d at 443.
The State contends that, after this Court rendered judgment in the appeal, the district court only had jurisdiction to enforce the appellate mandate. See Dallas County v. Sweitzer, 971 S.W.2d 629, 630 (Tex.App.Dallas 1998, no pet.) (district court has no *206jurisdiction to review or interpret appellate judgment). Our mandate only ordered the State to pay “costs” relating to the appeal, and thus, the state argues that the award of attorneys’ fees was beyond the scope of the mandate and outside of the district court’s jurisdiction.
There is a legitimate question as to whether a trial court’s order that is outside of the scope of an appellate mandate is void or merely voidable. The Houston Court of Appeals, Fourteenth District, thoroughly discussed the issue in Madeksho v. Abraham, Watkins, Nichols, & Friend, 112 S.W.3d 679, 685 (Tex.App.-Houston [14th Dist.] 2003, pet. denied) (en banc), and concluded that a trial court may abuse its discretion by issuing an order beyond the scope of an appellate mandate, but that subject-matter jurisdiction is not raised. The Dallas Court of Appeals has expressed the opposite position. See Dallas County v. Sweitzer, 971 S.W.2d 629, 630 (Tex.App.-Dallas 1998, no pet.); but see Kenseth v. Dallas County, 126 S.W.3d 584, 599 (Tex.App.-Dallas 2004, pet. denied) (order not void where trial court misinterpreted mandate). However, we need not resolve this question in this case because we find that the trial court had jurisdiction under section 37.011 of the declaratory judgment act.
Our review of the record indicates that the district court awarded attorneys’ fees as supplemental relief pursuant to section 37.011 of the declaratory judgment act. The issue was clearly framed as such in the district court’s order denying the State’s plea to the jurisdiction and the final judgment awarding attorneys’ fees cited sections 37.009 and 37.011 of the declaratory judgment act, not the appellate mandate.
Section 37.011 allows for further relief based on a declaratory judgment upon a showing that the relief is “necessary and proper.” Tex. Civ. Prac. & Rem. Code Ann. § 37.011 (West 1997); Texas Dep’t of Pub. Safety v. Moore, 985 S.W.2d 149, 156 (Tex.App.-Austin 1998, no pet.). Although we agree with the State that the declaratory judgment act does not independently create jurisdiction or substantive rights, see Continental Cas. Co. v. Rivera, 124 S.W.3d 705, 712-13 (Tex.App.-Austin 2003, pet. denied), section 37.011 of the act allows for the district court to grant relief ancillary to a prior declaratory judgment. See Genecov Group Inc. v. Roosth Prod. Co., 144 S.W.3d 546, 553 (Tex.App.-Tyler 2003, pet. denied); Moore, 985 S.W.2d at 157.
Courts have granted supplemental relief under the declaratory judgment act after an appeal and may award relief not requested on appeal. In Valley Oil Co. v. City of Garland, 499 S.W.2d 333, 335 (Tex.App.-Dallas 1973, no writ), Valley Oil successfully challenged, in the trial court, a city ordinance that would have forced it to close a gas station. The city appealed the issue of whether the ordinance was valid but did not raise the trial court’s denial of an injunction restraining Valley Oil from operating the gas station. The court of appeals reversed and rendered judgment that the ordinance was valid. Id. After the mandate from the court of appeals issued, the city again sought an injunction against Valley Oil based on the ordinance. Id. The trial court granted the injunction, and Valley Oil appealed contending that the City did not raise the issue of the injunction on appeal and was, therefore, precluded from further litigation on the matter. Id. The court of appeals affirmed the trial court’s order granting the injunction. Id. at 336. Despite the fact that the issue was not raised on appeal, the court explained that the city was entitled to further relief *207under the declaratory judgment act:2
The rationale for this apparent departure from the usual rule of res judicata is that the losing party in a declaratory judgment act can normally be expected to recognize the rights declared by the judgment and act accordingly, but that if he fails to do so, the court should have ample power to enforce the judgment by subsequent coercive orders, whether or not such relief was sought in the original action.
Id. at 336. The court of appeals specifically addressed the issue of jurisdiction, holding that the supplemental relief provision of the declaratory judgment act established jurisdiction, and that a request for relief may properly be brought in the same suit in which the original declaratory relief was granted. Id.
The dissent cites Howell v. Texas Workers’ Compensation Commission and Valley Oil for the proposition that the court’s power to grant ancillary relief under section 37.011 requires a showing that a party will not comply with the underlying declaratory judgment. See Howell, 143 S.W.3d 416, 433 (Tex.App.-Austin, no pet. h.); Valley Oil, 499 S.W.2d at 335-36. These cases confirm that the party seeking supplemental relief must make a showing that the requested relief is necessary and proper to enforce the declaratory judgment. See Howell, 143 S.W.3d at 433; Valley Oil, 499 S.W.2d at 335-36. They do not hold that a trial court lacks subject matter jurisdiction absent such a showing. A trial court’s jurisdiction to act does not simply dissolve if an appellate court later disagrees with that court’s determination that the relief was necessary and proper.
We also look to federal case law because section 37.002(c) of the declaratory judgment act compels us to construe the statute in harmony with federal law concerning declaratory judgments. See Tex. Civ. Prac. & Rem.Code Ann. § 37.002(c) (West 1997). The federal declaratory judgment act contains a “further relief’ provision similar to our statute. See 28 U.S.C. § 2202. Section 2202 authorizes the federal courts to grant “further necessary or proper relief based on a declaratory judgment or decree.” Id. A number of federal court decisions have made it clear that a trial court has jurisdiction to consider a request for “further relief1’ under the federal declaratory judgment act at any time, even after a completed appeal. See Insurance Sevs., of Beaufort, Inc. v. Aetna Cas. & Sur. Co., 966 F.2d 847, 851-52 (4th Cir.1992) (court retains jurisdiction to grant further relief to give effect to a declaratory judgment); Horn & Hardart Co. v. National Rail Passenger Corp., 843 F.2d 546, 548 (D.C.Cir.1988) (neither completed appeal nor lengthy period of delay deprives trial court of jurisdiction under 28 U.S.C. 2202); McNally v. American States Ins. Co., 339 F.2d 186, 187 (6th Cir.1964); In re Bicoastal Corp., 156 B.R. 327, 331 (Bankr.M.D.Fla.1993).
We hold that the district court had jurisdiction to consider the request pursuant to section 37.011 of the declaratory judgment act. See Valley Oil, 499 S.W.2d at 336; see also Insurance Servs., of Beaufort, 966 F.2d at 851-52; Horn & Hardart, 843 F.2d at 548. Whether the district court’s award of attorneys’ fees was “necessary or proper” will be addressed in the appeal pending before this Court. See Reiss, 118 S.W.3d at 443 (errors other than jurisdic*208tion to be corrected through ordinary appellate-process). The district court’s order awarding attorneys’ fees was not void and the State’s petition for a writ of mandamus is denied.
. By contrast, the dissent discusses issues of waiver and the merits of whether Anderson Courier's request for attorneys’ fees constitutes necessary and proper supplemental relief under section 37.011 of the declaratory judgment act. This is presumably because the dissent believes that the issue of jurisdiction is interrelated with the merits of Anderson Courier’s claim. Because we do not find that subject matter jurisdiction is implicated, we will refrain from addressing the dissent's arguments on the merits so as to avoid prejudging the State's appeal pending before us.
. The language of the declaratory judgment act’s supplemental relief provision cited in Valley Oil, is, in relevant part, identical to the current statute. Compare Tex. Civ. Prac. & Rem.Code Ann. § 37.011 (West 1997) with Tex.Rev.Civ. Stat. Ann. art. 2524-1 (Vernon 1965).
. I note that the trial court’s order stated that the attorney’s fees were “reasonable and necessary.” This tracks language used in section 37.009 of the UDJA, see Tex. Civ. Prac. & Rem.Code Ann. § 37.009 (West 1997), not section 37.011, which requires that supplemental relief be "necessary or proper.” Id. § 37.011 (West 1997). This is further indication that the trial court did not properly consider section 37.011 and its limited grant of power to give supplemental relief.