<telerik:GridViewComboBoxColumn Header="Location" DataMemberBinding="{Binding AlertLocationId}"
UniqueName="AlertLocation" SelectedValueMemberPath="Id" DisplayMemberPath="Name"
Style="{DynamicResource GridViewColumnStyle}"/>

publicclassAttributeListColumn: GridViewBoundColumnBase
    {
        public override FrameworkElement CreateCellElement(GridViewCell cell, object dataItem)
        {
            StackPanel mainContainer = new StackPanel
            {
                Orientation = Orientation.Horizontal
            };

            if (cell.DataContext != null)
            {
                string glyphResourceKey = ((cell.DataContext as System.Data.DataRow)[DataMemberBinding.Path.Path] as ListValueContainer)?.GlyphResourceKey;
                System.Windows.Shapes.Path path = new System.Windows.Shapes.Path
                {
                    Margin = new Thickness(0, 0, 5, 0),
                    Fill = System.Windows.Media.Brushes.Black,
                    Width = 13,
                    Height = 13,
                    Data = glyphResourceKey == null ? null : Application.Current?.TryFindResource(glyphResourceKey) as System.Windows.Media.Geometry,
                    Visibility = glyphResourceKey == null ? Visibility.Collapsed : Visibility.Visible
                };
                mainContainer.Children.Add(path);
            }

            //Add HighlightTextBlock to keep the SearchPanel functionality
            HighlightTextBlock htb = new HighlightTextBlock(DataControl.SearchStateManager);
            htb.SetBinding(HighlightTextBlock.HighlightTextProperty, new Binding($"[{DataMemberBinding.Path.Path}].Id"));
            cell.SetBinding(GridViewCell.IsHighlightedProperty, new Binding("ContainsMatch") { Source = htb, Mode = BindingMode.TwoWay });
            SetHighlightTextBlockTextProperty(dataItem, htb);
            mainContainer.Children.Add(htb);

            return mainContainer;
        }

        public void SetHighlightTextBlockTextProperty(object dataItem, TextBlock textBlock)
        {
            if (this.DataMemberBinding != null)
            {
                var content = this.GetCellContent(dataItem);
                if (content != null)
                {
                    textBlock.SetValue(TextBlock.TextProperty, (content as ListValueContainer).Id);
                }
            }
            else
            {
                textBlock.ClearValue(TextBlock.TextProperty);
            }
        }
    }

[TypeConverter(typeof(ListValueConverter))]
    public class ListValueContainer : IComparable, IEquatable<ListValueContainer>, INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;
        protected string glyphResourceKey;
        protected List<string> values = new List<string>();

        public ListValueContainer()
        {
        }

        public ListValueContainer(string value, string glyphResourceKey = null)
        {
            values.Add(value);
            this.glyphResourceKey = glyphResourceKey;
        }

        public ListValueContainer(List<AttributeListLookup> lookupValues, string glyphResourceKey = null)
        {
            if (lookupValues != null)
            {
                lookupValues.ForEach(a => values.Add(a.Id));
            }
            this.glyphResourceKey = glyphResourceKey;
        }

        public string GlyphResourceKey
        {
            get
            {
                return glyphResourceKey;
            }
        }

        public List<string> Values
        {
            get
            {
                return values;
            }
        }

        public string Id
        {
            get
            {
                return string.Join(", ", values);
            }
        }

        public virtual void OnPropertyChanged(PropertyChangedEventArgs args)
        {
            PropertyChangedEventHandler handler = this.PropertyChanged;
            if (handler != null)
            {
                handler(this, args);
            }
        }
}

foreach (var column in ItemGrid.Columns)
{
	column.Width = GridViewLength.Auto;
}

ItemGrid.EnableColumnVirtualization = false;                            

foreach (var column in ItemGrid.Columns)
{
	column.Width = GridViewLength.Auto;
	ItemGrid.ScrollIntoView(null, column);
	ItemGrid.UpdateLayout();
	column.Width = column.ActualWidth;
	column.IsSelected = true;
	column.Focus();
	column.Width = column.ActualWidth;
}

ItemGrid.UpdateLayout();

SaveLayout();

ItemGrid.EnableColumnVirtualization = true;