The CustomFilterDialogContent element's OK and Cancel buttons are different in size for the Windows 11 theme.

To work this around, you can subscribe to the Loaded event of the CustomFilterDialogContent element and retrieve the RadButton with x:Name="PART_ButtonCancel" via the ChildrenOfType extension method. On the retrieved button, set the VerticalAlignment property to Center.

The following code snippet showcases this suggestion's implementation:

static MainWindow()
{
    EventManager.RegisterClassHandler(typeof(CustomFilterDialogContent), LoadedEvent, new RoutedEventHandler(OnCustomFilterDialogContentLoaded));
}

private static void OnCustomFilterDialogContentLoaded(object sender, RoutedEventArgs e)
{
    RadButton cancelButton = ((CustomFilterDialogContent)sender).ChildrenOfType<RadButton>().FirstOrDefault(x => x.Name == "PART_ButtonCancel");

    if (cancelButton != null)
    {
        cancelButton.VerticalAlignment = VerticalAlignment.Center;
    }
}

The horizontal ScrollBar of RadSpreadsheet is missing the bottom border of its track. Additional to that there is a slight offset between the right end of the viewport and the right button of the ScrollBar.

To work this around, set the Margin of the horizontal ScrollBar to 0, and modify its ControlTemplate so that it adds a bottom border for the track's RepeatButton elements.

private void RadSpreadsheet_Loaded(object sender, RoutedEventArgs e)
{
    var spreadsheet = (RadSpreadsheet)sender;
    var scrollBar = spreadsheet.ChildrenOfType<ScrollBar>().FirstOrDefault(x => x.Name == "HorizontalScrollBar");
    scrollBar.Margin = new Thickness(0);
    scrollBar.Template = (ControlTemplate)this.Resources["MyCustomScrollBarTemplate"];
}

For the German language translations, the following resource keys are translated into Dutch instead:

• Spreadsheet_PrintPreview_FitSheetOnOnePage
• Spreadsheet_PrintPreview_FitSheetOnOnePage_Description
• Spreadsheet_PrintPreview_FitColumnsOnOnePage
• Spreadsheet_PrintPreview_FitColumnsOnOnePage_Description
• Spreadsheet_PrintPreview_FitRowsOnOnePage
• Spreadsheet_PrintPreview_FitRowsOnOnePage_Description

Improve the load time when the ribbon UI is used.

Add information about the selection in the SelectionChanged event arguments. 

- We need to differentiate from mouse event to keyboard event. But since the EventArgs is empty we are not able to differentiate.

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);
  }

Spreadsheet: Add the ability to build formulas using keyboard navigation: