Wis. Stat. § 856.19

Every will, when admitted to probate as prescribed by statute, shall have that fact signified thereon by the court. Without a prima facie showing of fraud, a mere allegation is not sufficient to require a court to reopen the admission of a will to probate after the time for appeal expired. In Matter of Estate of Kennedy, 74 Wis. 2d 413, 247 N.W.2d 75.