The numeric box that allows you to select the "to" page in the PrintPreviewControl is clipped when the "Pages:" and "to" strings are translated to a language where these words are longer. For example, this reproduces with Dutch culture which uses the "Pagina's:" and "naar" texts.

To work this around, you can get the Grid panel that hosts the content and increase the Width of one of its ColumnDefinitions.

  private void PrintPreviewControl_Loaded(object sender, RoutedEventArgs e)
  {
      var printPreview = (PrintPreviewControl)sender;
      var rootGrid = printPreview.FindChildByType<Grid>();
      rootGrid.ColumnDefinitions[0].Width = new GridLength(355);
  }