Last Updated: 16 Jun 2022 12:06 by ADMIN
Release R2 2022 SP1
The issue reproduces if you set the SelectedItem of the RadMultiColumnComboBox control before its textbox is loaded. One way for this situation to occur is if you data bind the SelectedItem to a property of the view model and then assign to the view model to the DataContext of the view, before the InitializeComponent call.

To work this around, you can reset the SelectedItem property on Loaded.

private void RadMultiColumnComboBox_Loaded(object sender, RoutedEventArgs e)
	var mccb = (RadMultiColumnComboBox)sender;            
	var selection = mccb.SelectedItem;
	mccb.SetCurrentValue(RadMultiColumnComboBox.SelectedItemProperty, null);
	mccb.SetCurrentValue(RadMultiColumnComboBox.SelectedItemProperty, selection);
Last Updated: 30 May 2022 09:14 by ADMIN
Release LIB 2022.2.530 (30 May 2022)

When the SelectionMode of MultiColumnComboBox is set to Single, changing the Selection invokes twice the SelectionChanged event.

What I would expect is that the event fires only once, with one item in AddedItems and one item in RemovedItems. Currently, addition and removal is done seperately, and the two invocations of the event correspond to them.

To reproduce, just use the Getting Started article about MultiColumnComboBox with the Clubs ItemSource. Subscribe to SelectionChanged event and make a change to the selection. I hope the following gif makes this clear - the first selection is valid, but the second should invoke the event only once, with 1 item added, 1 removed.

Last Updated: 07 Jan 2022 07:09 by ADMIN
Release R1 2022

The drop-down menu does not close when a context menu is opened on top of it, even if the KeepDropDownOpen="False". The control would need to move the focus in order for the drop-down to close.

To work this around, you can use the CloseDropDown() method of the MultiColumnComboBox control.

Last Updated: 20 Sep 2021 07:04 by ADMIN
Release LIB 2021.3.920 (20 Sep 2021)
The search text gets cleared when a click on the combobox occurs (to open a combobox). No selection is performed during this action.

To work this around, you can cache the search text just before it is cleared and then restore it after the selection is performed.
Last Updated: 02 Aug 2021 08:02 by ADMIN
Release LIB 2021.2.802 (2 Aug 2021)

When placing controls in the CellTemplate/CellEditTemplate in the RadMultiColumnComboBox`s dropdown`s GridView some do not receive/accept the mouse input correctly.

In the newest version (2021.2.615) the dropdown of a RadDatePicker does not open. A RadButton works fine and a RadComboBox open and can select an item via mouse click.

In a previous version (2021.1.325) the RadComboBox also does not work, this seems to be fixed already.


I have attached a sample project demonstrating the behavio:

1) start the project

2) open the dropdown of the RadMultiColumnComboBox

3) click on the RadDatePicker`s calender icon button. => the calender view does not open

The very same DataTemplate is applied obove the RadMultiColumnComboBox to illustrate the proper behavior in contrast.


The behavior is visually demonstrated in the .gif (1.gif and 2.gif) I have attached.

Last Updated: 20 May 2021 07:14 by ADMIN
Release LIB 2021.2.525 (25/05/2021)

If you host RadMultiColumnComboBox in a control with a vertical ScrollViewer, then open the popup content of the RadMultiColumnComboBox and use the mouse wheel in it, the parent ScrollViewer scrolls. In comparison RadComboBox and the native WPF ComboBox are not scrolling. Instead the scrolling event is consumed and it doesn't propagate to the parent ScrollViewer.

The attached project shows one way to work this around.

Last Updated: 03 Mar 2021 11:12 by ADMIN
GridViewMultiColumnComboBoxColumn does not have any selected value in edit mode when SelectionBoxesVisibility is set to Collapsed/Hidden and AutoCompleteMode is Search/Suggest.
Last Updated: 04 Nov 2020 10:30 by ADMIN
When the SelectedBoxesVisiblity property is set to Collapsed and the SelectedItem is bound, no text appears in the control when an item is select.
Last Updated: 15 Oct 2020 14:30 by ADMIN
Release R3 2020 SP1
The received exception is: "System.ArgumentNullException: 'Value cannot be null.
Parameter name: source'".
Last Updated: 28 Sep 2020 09:54 by ADMIN
Release LIB 2020.3.928 (09/28/2020)
Selecting an item is not possible after the RadGridView control in the dropdown has been sorted.
Last Updated: 31 Aug 2020 10:40 by ADMIN
Release LIB 2020.2.831
When the filtered items in the RadGridView do not contain the currently selected items, they are cleared. 
Last Updated: 21 May 2020 08:28 by ADMIN
Release LIB 2020.2.526 (05/26/2020)

If you select an item in RadMultiColumnComboBox and then replace the ItemsSource of the GridViewItemsSourceProvider, the selection in the autocompletebox part of the the control is not cleared. There are items that are still selected and are not presented in the ItemsSource.

To work this around, you can create a custom GridViewItemsSourceProvider and override its OnPropertyChanged method. When the ItemsSource is changed, you can reset the selection.

public class CustomGridViewItemsSourceProvider : GridViewItemsSourceProvider
	public RadMultiColumnComboBox Owner
		get { return (RadMultiColumnComboBox)GetValue(OwnerProperty); }
		set { SetValue(OwnerProperty, value); }
	public static readonly DependencyProperty OwnerProperty =
			new PropertyMetadata(null));

	protected override void OnPropertyChanged(DependencyPropertyChangedEventArgs e)
		if (e.Property.Name == "ItemsSource" && this.Owner != null)

                <local:CustomGridViewItemsSourceProvider Owner="{Binding ElementName=mccb}" />

Last Updated: 10 Apr 2020 05:07 by ADMIN
Release LIB 2020.1.413 (04/13/2020)
InvalidOperationException is thrown when programmatically adding items to the SelectedItems collection after the dropdown has been opened.
Last Updated: 10 Feb 2020 16:26 by ADMIN
Release LIB 2020.1.210 (02/10/2020)

The following error is thrown when the dropdown of the control is opened: Cannot find governing FrameworkElement or FrameworkContentElement for target element. ... ; target element is 'GridViewItemsSourceProvider; target property is 'ItemsSource' (type 'Object')

If the combobox is placed inside a RadGridView, the error is thrown each time the dropdown is opened (after a commit action).

Last Updated: 29 Jan 2020 15:02 by ADMIN
Release LIB 2020.1.203 (02/03/2020)

The Validation.ErrorTemplate attached property is not set. To workaround this, you can use the following resource.

<ControlTemplate x:Key="ValidationTooltipTemplate">
    <Grid SnapsToDevicePixels="True" VerticalAlignment="Top">
        <Border Background="Transparent" HorizontalAlignment="Right" VerticalAlignment="Top" Width="3" Height="3"/>
        <AdornedElementPlaceholder x:Name="Holder"/>
        <Border BorderBrush="{StaticResource ValidationTooltipOuterBorder}" BorderThickness="1" CornerRadius="{StaticResource ValidationTooltip_CornerRadius}"/>
        <Path Data="M2,1 L6,1 6,5 Z" Fill="{StaticResource ValidationInnerTick}" Width="7" Height="7" HorizontalAlignment="Right" VerticalAlignment="Top"/>
        <Path Data="M0,0 L2,0 7,5 7,7 Z" Fill="{StaticResource ValidationOuterTick}" Width="7" Height="7" HorizontalAlignment="Right" VerticalAlignment="Top"/>
            <ToolTip x:Name="PART_ToolTip"
                DataContext="{Binding RelativeSource={RelativeSource Mode=Self}, Path=PlacementTarget.DataContext}"
                Template="{StaticResource ErrorTooltipTemplate}"

<Style TargetType="telerik:RadMultiColumnComboBox" BasedOn="{StaticResource RadMultiColumnComboBoxStyle}">
    <Setter Property="Validation.ErrorTemplate" Value="{StaticResource ValidationTooltipTemplate}" />

Last Updated: 18 Nov 2019 11:55 by ADMIN
Release LIB 2019.3.1118 (11/18/2019)
Dropdown does not close when OpenDropDownOnFocus is True and KeepDropDownOpen is False and the user has previously made a selection after opening the control by clicking on its textbox part.
Last Updated: 15 Nov 2019 14:03 by ADMIN
Release LIB 2019.3.1118
A NullReferenceException is thrown after opening the dropdown and there is an implicit style targeting RadGridView which sets the SearchMode property.
Last Updated: 07 Nov 2019 11:02 by ADMIN
Created by: Mats
Comments: 3
Category: MultiColumnComboBox
Type: Bug Report

Hi Telerik-Team,


i found a bug similar to forum post, but not the same.

In MultiColumnComboBox when SelectionBoxesVisibility is set  to 'collapsed' and and whatever you set AutoCompleteMode to (different from the forum post),

if you select the first item it is not shown. Although the NullText is removed. It works perfectly for all the other items. This is quiet a problem if you only have one item in the dropwdown :D




Last Updated: 02 Aug 2019 10:32 by ADMIN
Release LIB 2019.2.805 (8/05/2019)

If set the AutoCompleteMode property in a Style Setter, and exception is thrown.

To work this around set the property directly on the control.
<telerik:RadMultiColumnComboBox AutoCompleteMode="Search" />

1 2