An en banc panel of the Pennsylvania Commonwealth Court in Mandler v. Pennsylvania overruled the taxpayers’ exceptions to a prior panel’s opinion. The taxpayers claimed that they were entitled to the return of certain payroll taxes paid to the Department of Revenue in the course of the taxpayers’ consolidated bankruptcy proceedings. Though the Court generally quoted at length from the prior panel’s opinion, the en banc panel opinion elaborated on the taxpayers’ argument based on estoppel by laches. The Court noted that the passage of time would not alone obviate a taxpayer’s liability to the Department of Revenue, though perhaps estoppel by laches could compel the Department to forgo penalties for late payments.