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: 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: 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: 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: 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: 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: 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: 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: 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: 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" />

Last Updated: 15 Feb 2019 14:25 by ADMIN
Created by: WSB
Comments: 2
Category: MultiColumnComboBox
Type: Bug Report

Hello Telerik,

Exception is thrown after typing in the autocompletebox and selecting an item right after that. 

  Message=Exception has been thrown by the target of an invocation.
   at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
   at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments)
   at System.Delegate.DynamicInvokeImpl(Object[] args)
   at System.Windows.RoutedEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
   at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
   at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
   at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   at System.Windows.UIElement.RaiseEvent(RoutedEventArgs e)
   at Telerik.Windows.Controls.GridView.GridViewDataControl.RaiseSelectionChangedEvent(SelectionChangeEventArgs args)
   at Telerik.Windows.Controls.DataControl.RaiseSelectionChangedEvent(ItemSelectionChange selectionChange)
   at Telerik.Windows.Controls.DataControl.Telerik.Windows.Data.Selection.ISelectorInternal.RaiseSelectionChangedEvent(ItemSelectionChange selectionChange)
   at Telerik.Windows.Data.Selection.ItemSelectionHandler.EndAllowedSelection(ItemSelectionChange selectionChange)
   at Telerik.Windows.Data.Selection.ItemSelectionHandler.EndPendingSelection(ItemSelectionChange pendingSelection)
   at Telerik.Windows.Data.Selection.ItemSelectionHandler.EndSelection()
   at Telerik.Windows.Data.Selection.ItemSelectionHandler.SelectedItems_CollectionChanged(Object sender, 

Thanks in advance.


Last Updated: 16 Feb 2019 10:24 by ADMIN
If you set the SelectionMode of the control to Multiple the SelectionChanged event fires only when you select item for the first item. Each next selection won't fire the event.

To work this around use to CollectionChanged event of the SelectedItems collection of RadMultiColumnComboBox.
Last Updated: 15 Feb 2019 09:08 by ADMIN

The event should fire when the DropDownContentManager gets initialized.

To work this around use the InitializeSelectionBridge event. The DropDownContentManager is initialized when this event fires.

Last Updated: 03 Jan 2019 11:52 by ADMIN
Created by: Tino
Comments: 2
Category: MultiColumnComboBox
Type: Bug Report



when selecting more items and dropdown positioning is down and input filed has fixed width, the dropdown covers the input field.

It should move down to the bottom edge of input field.


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