InvalidOperationException: Cannot set Visibility to Visible or call Show, ShowDialog, Close, or WindowInteropHelper.EnsureHandle while a Window is closing.
StackTrace:
   at System.Windows.Window.VerifyNotClosing()
   at System.Windows.Window.InternalClose(Boolean shutdown, Boolean ignoreCancel)
   at System.Windows.Application.DoShutdown()
   at System.Windows.Application.ShutdownImpl()
   at System.Windows.Application.ShutdownCallback(Object arg)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)