Last Updated: 27 May 2020 16:18 by Patrick
Created by: Tanya
Comments: 3
Category: PDFViewer
Type: Feature Request
In Adobe and Foxit readers, the user can draw different shapes, which are later saved as images in the document.
Last Updated: 27 May 2020 10:45 by ADMIN
A NullReferenceException is raised when trying to edit a GridViewMultiColumnComboBoxColumn and the RadGridView's ItemsSource is a DataView.
Last Updated: 27 May 2020 06:57 by ADMIN
Created by: LindenauAtSOG
Comments: 3
Category: GridView
Type: Bug Report
As a Followup to this (Bad performance with grouping)Forumpost I managed to reproduce the issue now.
Since i cannot upload zip-files in the Forum I am doing it here.

The problem is, that a single grouping dramatically increases the time for sorting the values.
When the grouping is not present, sorting the same column is much faster.

It appears that it is related to the ammount of columns in total (not grouped).
The ammount of records is not so important, 100 (as in the attached sample) should not be significant.
Last Updated: 26 May 2020 16:16 by ADMIN

The check mark of the RadioButton is misaligned when DPI settings are set to a higher than the default value, e.g. 125%.

The problem can easily be reproduced using the Telerik UI for WPF Demo application:

Won't Fix
Last Updated: 26 May 2020 15:27 by Petar

" Collection was modified; enumeration operation may not execute.'" - The exception is observed when the CLR exceptions are enabled from Visual Studio. 


The Ellapsed event handler of the Timer is executed in background thread but modifying chart data in a background thread is considered bad practice which is not supported by our component. This is the reason we are declining this bug report.

General solution is to schedule the data update to happen on the UI thread with Dispatcher. When in ViewModel, the following code can be used:

        private void OnTimerElapsed(object sender, ElapsedEventArgs e)
            ViewModelBase.InvokeOnUIThread(() =>
                for (int i = 0; i < Items.Count; i++)
                    Items[i].X += (_random.NextDouble() - 0.5) * 0.1;
                    Items[i].Y += (_random.NextDouble() - 0.5) * 0.1;
Last Updated: 26 May 2020 15:02 by ADMIN
Created by: prashant
Comments: 1
Category: Chat
Type: Feature Request


Quick question on solution provided in the ticket : https://www.telerik.com/account/support-tickets/view-ticket/1464733 . 

It looks like we would need to show few SuggestedAction in vertical and others in horizontal orientation. Is it possible to set the orientation value from chat control ? 

Something like this ...


<VirtualizingStackPanel IsItemsHost="True" Orientation="{Binding RelativeSource={RelativeSource AncestorType={x:Type telerik:RadChat}},



Last Updated: 26 May 2020 11:40 by ADMIN

It appears the ChartView is also affected by the same SharpDX issue that affected the RadWebCam when it is used over Remote Desktop. 

A simple test of any series will replicate the issue. If it is being used via Remote Desktop, the series will not render.

In Development
Last Updated: 26 May 2020 08:47 by ADMIN
Created by: Martin Ivanov
Comments: 0
Category: DesktopAlert
Type: Feature Request
Allow playing sound when the RadDesktopAlert opens similar to the WinForms feature.
Last Updated: 26 May 2020 08:34 by ADMIN
Release LIB 2020.2.525 (5/26/2020)
The Visibility of the DropPossibleIconElement inside the ControlTemplate of the TreeListViewDragCue is not collapsed when the drop is not possible in newer themes. 
Last Updated: 26 May 2020 08:34 by ADMIN
Release LIB 2020.2.525 (5/26/2020)

Select nested item in virtualized treeview with single selection mode.

Collapse its parent. Select item in the level of the parent. Expand the parent and notice two items are visually selected.

Expexted : only the last selected item with mouse should be visually selected.


private void TreeView_ItemPrepared(object sender, RadTreeViewItemPreparedEventArgs e)
    if ((e.PreparedItem.IsSelected == true && this.TreeView.SelectedItem != null && this.TreeView.SelectedItem != e.PreparedItem.Item))
        e.PreparedItem.IsSelected = false;
Last Updated: 26 May 2020 08:34 by ADMIN
Release LIB 2020.2.525 (5/26/2020)
Created by: Dinko
Comments: 0
Category: TileView
Type: Bug Report
The UnselectAll method, which comes from MultiSelector, does not unselect all items when manually select them one by one. The method will unselect the items in the order they were selected, one by one.
Last Updated: 26 May 2020 08:34 by ADMIN
Release LIB 2020.2.525 (5/26/2020)
A XamlParseException is raised when binding to the ShowAppointmentDeleteButton property of the RadScheduleView. 
Last Updated: 26 May 2020 08:34 by ADMIN
Release LIB 2020.2.525 (5/26/2020)
External MapScale object does not update until you Zoom/Move the map
Last Updated: 26 May 2020 08:34 by ADMIN
Release LIB 2020.2.525 (5/26/2020)
 IndexOutOfRangeException is thrown when deleting files while the FileDialog is loading.
Last Updated: 26 May 2020 08:34 by ADMIN
Release LIB 2020.2.525 (5/26/2020)

While performing Cut operation inside RadDiagram, an exception in the MS Clipboard occurs with the following message:

System.Runtime.InteropServices.COMException: 'OpenClipboard Failed (Exception from HRESULT: 0x800401D0 (CLIPBRD_E_CANT_OPEN))'

Last Updated: 26 May 2020 06:58 by ADMIN
Created by: Martin Ivanov
Comments: 0
Category: ChartView
Type: Feature Request
Allow setting OriginValue on the series in the RadPolarChart. Currently, the area series are fixed to OriginValue of 0.

The same feature is available in the RadCartesianChart series.
Under Review
Last Updated: 26 May 2020 06:48 by Valentin
Created by: Valentin
Comments: 3
Category: UI for WPF
Type: Feature Request

It would be awesome if the user would be able to create folders for visual organization in tree views, tree list views and list views. These folders should not be actual items in the tree, but rather be a visual simplification for complex lists and trees.

Folder specific features:

  • Add, move, rename and delete folders
  • Add or move items to the folders (for example via drag&drop)
  • Move and delete folders with their content
  • Verification, if certain types are allowed in a folder
  • Sort the content of the folder

    View specific features

  • Switch between “folder view” and “folderless view”
  • Save and load structures, similar to the LayoutControl
  • Verification, if a folder is allowed to be moved to or created in certain areas
  • Possibility to manipulate the structure from the code

With this feature the user would find it easier to organize sometimes complex trees and lists into manageable folder structures, as the layout would be created by the user himself. The folders also make collective operations on items in them easier to handle, as the user can move or delete the folder with its content and does not need to select long lists of items for every operation. This would increase the usability of the trees and lists.

Last Updated: 22 May 2020 12:42 by ADMIN

For example:

some text // some comment

some text 2 // some comment 2

Specified argument was out of the range of valid values.
Parameter name: span



at Telerik.Windows.SyntaxEditor.Core.Text.DataStructures.ConcatenationRopeNode.GetText(Span span) in C:\WPF_Scrum\Current\Controls\SyntaxEditor\SyntaxEditor.Core\Text\DataStructures\ConcatenationRopeNode.cs:line 140
   at Telerik.Windows.SyntaxEditor.Core.Text.TextSnapshot.GetText(Span span) in C:\WPF_Scrum\Current\Controls\SyntaxEditor\SyntaxEditor.Core\Text\TextSnapshot.cs:line 118
   at Telerik.Windows.Controls.SyntaxEditor.Taggers.CSharpFoldingTagger.GetFoldingRegionTitle(String inputValue, Span span, String startText) in C:\WPF_Scrum\Current\Controls\SyntaxEditor\SyntaxEditor\Taggers\Folding\CSharpFoldingTagger.cs:line 202

Need More Info
Last Updated: 22 May 2020 11:47 by ADMIN

Hi guys,

we have a messaging service that broadcasts a couple of messages every 1-5 seconds.

When our client module receives those messages, we want to append them at the bottom of a grid (RadGridView).

After appending them, we also want to scroll to the very bottom of that grid, so that the newest and therefore bottommost items come into view.


Documentation and forums suggest we go the AttachedBahaviour and ScrollIntoViewAsync way.


Our behaviour looks like this:

    public class ScrollToNewItemBehavior : Behavior<RadGridView>
        public static bool GetIsEnabled(DependencyObject obj) => (bool)obj.GetValue(IsEnabledProperty);
        public static void SetIsEnabled(DependencyObject obj, bool value) => obj.SetValue(IsEnabledProperty, value);
        public static readonly DependencyProperty IsEnabledProperty = DependencyProperty.RegisterAttached("IsEnabled", typeof(bool), typeof(ScrollToNewItemBehavior), new PropertyMetadata(false, OnIsEnabledChanged));
        private static void OnIsEnabledChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
            if (d is RadGridView gridView)
                gridView.Items.CollectionChanged += (s, args) =>
                    if (args.Action == NotifyCollectionChangedAction.Add)
                        gridView.ScrollIntoViewAsync(args.NewItems[0], gridView.Columns[0], null);

                        // exchanging args.NewItems[0] for gridView.Items[gridView.Items.Count-1] yields same result
                        //gridView.ScrollIntoViewAsync(gridView.Items[gridView.Items.Count-1], gridView.Columns[0], null);


Our Message class:

    public class Message : ModelBase<Message>
        public string Text { get; set; }

Our Messages collection in the ViewModel:

        private RadObservableCollection<Message> _messages;
        public RadObservableCollection<Message> Messages
            get => _messages;
                _messages = value;
                NotifyPropertyChanged(m => m.Messages);

The collection is updated (in the ViewModel) like this:

            Task.Run(async () =>
                for (int i = 0; ; i++)
                    await Task.Delay(1000);
                    Messages.Add(new Message { Text = $"{i} - sftrvwj,erhvtwejhrfvtjlwehftrwejh" });


The grid is defined like this:

        ItemsSource="{Binding Messages, Mode=OneWay}"
                DataMemberBinding="{Binding Text}"

Nothing too fancy.


What we observe:


When a message is added, the view and the scroll indicator randomly jump to the top or the bottom of the grid and stay there until the next message is added.

We tried AddRange, Suspend-/ResumeNotifications, ObservableCollection instead of RadObservableCollection.

We disabled many grid features.

We tried .NetCore


we tried .net Framework

To no avail.

This seems to be a bug.


Do you know any workarounds or a completely different approach to achieve the desired behaviour?



Side note:

When we set GroupRenderingMode to Flat,


the view stays at the bottom. The scroll indicator stays at the bottom as well, but once in a while jumps a little bit up, as if by one row, and down to the bottom again without the view changing.

At one time disabling filtering on all columns seemd to work... but later didn't.



Thanks in advance


In Development
Last Updated: 22 May 2020 10:17 by ADMIN
When you select a time span at the beginning of the period, the left thumb is not visible. Issue is reproducible with our Fluent theme.
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