Wis. Stat. § 809.18
This section does not require the dismissal of a petition for a supervisory writ upon the filing of a notice of voluntary dismissal. A petition for a supervisory writ is not an "appeal." Interest of Peter B. 184 Wis. 2d 57, 616 N.W.2d 746 (Ct. App. 1994). The court of appeals must dismiss an appeal when an appellant files a notice of voluntary dismissal before the court issues its decision on the appeal. State v. Lee, 197 Wis. 2d 960, 542 N.W.2d 143 (1996). The date stamped on a court of appeals decision or order is the date it is issued and filed. That the clerk's office mails appellate decisions to the parties the day before they are dated and filed does not mean that decisions are to be deemed to have been issued on the mailing date. A notice of voluntary dismissal filed on the day prior to an opinion being issued operates to automatically dismiss the appeal. State v. Jones, 2002 WI 53, 252 Wis. 2d 592, 645 N.W.2d 610, 01-1155.