The cell content gets clipped when the width of the previous column changes at runtime. This happens in the Windows11 and Office2019 themes (possibly in others) and only if the clipped cell is position before the right frozen columns area.

To work this around, you can call the Rebind() method of RadGridView, after the column width changes.

In the Office2019 theme, the RadGridView's ScrollBar elements should have transparent background by design. This is the track's background shown behind the thumb element that allows drag-to-scroll. Currently, the ScrollBars have a gray background.

To work this around, you can define an implicit Style in the App.xaml that targets the GridViewScrollViewer control. Then, set its Background property.

<Application.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="/Telerik.Windows.Themes.Office2019;component/Themes/System.Windows.xaml"/>
            <ResourceDictionary Source="/Telerik.Windows.Themes.Office2019;component/Themes/Telerik.Windows.Controls.xaml"/>
            <ResourceDictionary Source="/Telerik.Windows.Themes.Office2019;component/Themes/Telerik.Windows.Controls.Input.xaml"/>
            <ResourceDictionary Source="/Telerik.Windows.Themes.Office2019;component/Themes/Telerik.Windows.Controls.GridView.xaml"/>
        </ResourceDictionary.MergedDictionaries>
        <Style TargetType="telerik:GridViewScrollViewer" BasedOn="{StaticResource GridViewScrollViewerStyle}">
            <Setter Property="Background" Value="Transparent"/>
        </Style>
    </ResourceDictionary>
</Application.Resources>

The column group headers are not displayed when the DisplayIndex property of the GridViewColumn objects is set before the control is loaded.

To work this around, you can set the DisplayIndex of the columns after the RadGridView is loaded.

InvalidCastException is thrown when the DropIndicatorThickness property of the GridViewHeaderCell is set. Or whenever the DropIndicatorBrush property is accessed. This happens when using the Windows 7 theme. Also, the EnableColumnVirtualization property should be set to False.

System.InvalidCastException: 'Unable to cast object of type 'System.Windows.Media.LinearGradientBrush' to type 'System.Windows.Media.SolidColorBrush'.'

To work this around, you can use an implicit style targeting the GridViewHeaderCell in order to set its DropIndicatorBrush to a SolidColorBrush value.

 <telerik:RadGridView.Resources>
     <Style TargetType="telerik:GridViewHeaderCell">
         <Setter Property="DropIndicatorBrush" Value="White" />
         <Setter Property="DropIndicatorThickness" Value="10" />
     </Style>
 </telerik:RadGridView.Resources>

I already have a work-around and I don't have time to craft an example.

When running two dispatchers in different threads, ie launching the following code twice:

public void LaunchInThread()
        {
            Thread _thread = new Thread(() =>
            {
              Application app = new Application();
              app.Run(new Window());
            });
            _thread.SetApartmentState(ApartmentState.STA);
            _thread.Start();
        }

And setting column hierarchical column headers to some but not all columns by code, ie:

if( ! first_column){
   column.ColumnGroupName = "groupName";
   if (radGridView.ColumnGroups.FirstOrDefault(x => x.Name == "groupName") != null) return;
   radGridView.ColumnGroups.Add(new GridViewColumnGroup { Header = "groupName", Name = "groupName" });
}

My guess is that when no header is set, by default an static empty GridViewColumnGroup is reused. And as it's non-freezable it crashes.

I have a GridView, with  ClipboardCopyMode set to "Cells, Header" and defined event CopyingCellClipboardContent :

private void RadGridView1_CopyingCellClipboardContent(object sender, GridViewCellClipboardEventArgs e)
{
// _excludedcolumns = columns excluded from copy operation set in logic before
if (_excludedcolumns.Contains(e.Cell.Column))
{
e.Cancel = true;
}
}

Header cells are empty, not skipped like ordinary cells.

Regards
Janez

The result string contains wrong header positions and some headers could be missing when the copy of cells (including the header cells) of a column is cancelled using the CopyingCellClipboardContent event. This happens when the ClipboardCopyMode is set to "Cells,Header". 

To work this around, you can override the Copied event and replace the string part from the clipboard that contains the headers, with your custom variant.

private void RadGridView_Copied(object sender, Telerik.Windows.RadRoutedEventArgs e)
{
	string copiedData = Clipboard.GetText();
	int headerEndIndex = copiedData.IndexOf("\r\n");
	string headerString = copiedData.Substring(0, headerEndIndex) + "\r\n";
	copiedData = copiedData.Remove(0, headerEndIndex);

	var gridView = (RadGridView)sender;
	var filteredColumns = gridView.Columns.OfType<Telerik.Windows.Controls.GridViewColumn>()
		.OrderBy(x => x.DisplayIndex)
		.Where(x => x.IsVisible && !excludedColumns.Contains(x));
	// Where excludedColumns list contains the columns that shouldn't be copied. In this example, this collection is used in the CopyingCellClipboardContent event handler to remove the corresponding columns from the clipboard copy process.

	string newHeader = string.Empty;
	for (int i = 0; i < filteredColumns.Count(); i++)
	{
		var column = filteredColumns.ElementAt(i);
		newHeader += column.Header.ToString();
		if (i < filteredColumns.Count() - 1)
		{
			newHeader += "\t";
		}

	}
	copiedData = newHeader + copiedData;
	Clipboard.SetText(copiedData);
}

Setting ShowDistinctFilters for a RadGridViewColumn hides the distinct values from the filter popup as expected.

But the grid still queries the ItemsSource for distinct values of said column when showing thje popup - it calls something like

MyQueryable.Select(item => item.SomeColumn).Distinct().OrderBy(item => item).Take(1000))

The first two pinned rows are scrolled outside of the viewport when you scroll. For example, if you pin 4 rows, the first two will be scrolled and you will see only the second two pinned. This reproduces in the Green, Windows 11, Crystal and Office2019 themes.

To work this around, set the UseLayoutRounding property of RadGridView to "False". Or use a different Telerik theme.