Last Updated: 03 Jun 2024 13:31 by Petar
SelectedItems collection not updated when items are removed
Last Updated: 28 May 2024 08:17 by ADMIN

We use a RadTreeView with many different item types that set a DefaultImageSrc based on a combination of item type and state
(from each item's view model).

For the currently selected TreeView item we would like to modify the item's image with a coloured border.
So it would be a very useful feature, if the TreeView item's SelectedImage could be derived from the DefaultImageSrc
via XAML Shapes (Rectangle, Line, etc.).
(Shapes can e.g. already be used to draw TreeView's Expander-Button for expanded/collapsed state, which is very useful).

Currently the only approach is to copy any item-type's image in the file system and modify it for selected state.
(Thus doubling the number of item image files.)
Given the number of images for different item types and states that we already have, this is not very practical.

Examples for DefaultImageSrc (left) and SelectedImageSrc (right):

  •  -> 
  •  -> 

Is it possible to extend RadTreeView, so that the SelectedImageSrc can be based on the given DefaultImageSrc, but with a modification provided via XAML?

Last Updated: 11 Apr 2024 08:43 by Petar
Created by: Laurent Kempé
Comments: 14
Category: UI for WPF
Type: Feature Request


I would like to know if Progress Telerik has some plan to port their WPF controls to Avalonia (




Last Updated: 09 Apr 2024 08:27 by ADMIN
XObejcts with indirect reference to an image are not rendered.
Last Updated: 20 Mar 2024 11:34 by Petar
The ExportToImage method of the RadDiagram control does not take into account transforms applied to the diagram items.
Last Updated: 29 Feb 2024 07:39 by ADMIN

I have no idea how to reproduce this, but every so often after a paste operation into a RadRichTextBox, the host thread becomes unresponsive to user input. The message pump is still running but the following unhandled exception gets thrown in a tight infinite loop. The only way to close the window is to right click on the taskbar button.

Message: Object reference not set to an instance of an object.
Call Stack:
    at Telerik.Windows.Documents.Layout.LayoutElement.SetParent(LayoutElement newParent)
    at Telerik.Windows.Documents.Layout.LayoutBox.EnsureParent()
    at Telerik.Windows.Documents.Layout.LayoutBox.get_Parent()
    at Telerik.Windows.Documents.Layout.FormattingSymbolLayoutBox.get_IsEndOfCell()
    at Telerik.Windows.Documents.Layout.FormattingSymbolLayoutBox.GetFormattingSymbolVisual()
    at Telerik.Windows.Documents.SpanBoxPositionHandler.get_Location()
    at Telerik.Windows.Documents.UI.DocumentWebLayoutPresenter.GetViewPointFromDocumentPosition(DocumentPosition position)
    at Telerik.Windows.Controls.RichTextBoxUI.PasteOptionsPopup.CalculateLocation()
    at Telerik.Windows.Controls.RichTextBoxUI.PasteOptionsPopup.OnOwnerLayoutUpdated(Object sender, EventArgs e)
    at System.Windows.ContextLayoutManager.fireLayoutUpdateEvent()
    at System.Windows.ContextLayoutManager.UpdateLayout()
    at System.Windows.ContextLayoutManager.UpdateLayoutCallback(Object arg)
    at System.Windows.Media.MediaContext.FireInvokeOnRenderCallbacks()
    at System.Windows.Media.MediaContext.RenderMessageHandlerCore(Object resizedCompositionTarget)
    at System.Windows.Media.MediaContext.RenderMessageHandler(Object resizedCompositionTarget)
    at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
    at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)


Last Updated: 09 Feb 2024 08:26 by ADMIN

Dear Telerik Support Team,

I am encountering an issue with the RadGridView control in my application, which is impacting the usability for users relying on screen readers. Below, I have outlined the details of my development environment, the problem, and attached a sample project demonstrating the issue.

Issue Description:
In the attached sample project, I have implemented a simple RadGridView without any custom styling and populated it with sample data. I have observed that the focus behavior is inconsistent, particularly with the first cell in the RadGridView. When attempting to focus the first cell, only the cell itself receives focus, unlike subsequent cells where both the cell and the entire row are focused. This inconsistency results in screen readers failing to read out the content of the first cell, while they correctly read the contents of all other cells.

Upon further investigation using the Snoop utility to explore the visual tree, I noticed that the GotFocused event for the initially focused cell identifies it as being of type RadGridView, whereas, for other cells, the type is GridViewCell. This discrepancy seems to be at the root of the issue.

I have included a simplified, runnable standalone application that reproduces this behavior. Please find the sample project attached to this ticket.

I believe this might be a bug affecting the accessibility of the application, and I would greatly appreciate your guidance on whether this is a known issue with a workaround or if there's a fix available.

Thank you for your assistance.

Best regards,



First Tab:

Second Tab:

Last Updated: 19 Dec 2023 09:19 by ADMIN

HeaderSizeNeeded is fired twice with the same index and affects the header row width. 

Last Updated: 07 Dec 2023 07:59 by ADMIN

After using Direct2D in ChartView, zoom in/zoom out/pan , finally shrink back to the original size. After many iterations, it is possible that the Scatter spline will be shifted, if don't use Direct2D or use the Net Framework,Such problems do not arise.

 Please check the attachment.


Last Updated: 31 Oct 2023 13:36 by ADMIN
Item is automatically changed when pressing the tab key to leave the control
Last Updated: 26 Oct 2023 16:10 by ADMIN
Theme color variation does not get applied in the XAML designer in Visual Studio 2022.
Last Updated: 25 Oct 2023 08:58 by ADMIN
The RadDocument.MailMerge() function crashes a service after the mail merge is ran several times
Last Updated: 24 Oct 2023 15:19 by ADMIN


Since we want to boost up the performance of the ScheduleView , we've applied the 2023_2_718 UI for WPF to enable the virtualization of the group headers with setting the property  IsGroupHeadersVirtualizationEnabled="True". However we've experienced issues also with rendering for the appointments and group headers(resources) when scrolling.

In one of the screens where the schedule view is used, the group headers don't have equal sizes, for example:

The height may vary depending on the overlapping appointments for the resource which is allowed for our system. 

There is a note that there might be issues and unexpected behavior when the headers have different sizes claimed here:

WPF ScheduleView - UI Virtualization - Telerik UI for WPF

In this scenario we experience multiple issues, like for example when scrolled at the bottom, and the schedule view is fully refreshed, the resources and appointments are not rendered :

until it's scrolled.

Also when scrolling, we experience a "blinking" rendering, the group headers change sizes on scrolling :



Can you please let us know if/when this is planned to be fixed.


Another issue not related to the header size differences is that some of the appointments are lost (not rendered)  when the height of the schedule view is changed resulting in some of the appointments to not be visible anymore .The selection is kept on the group headers, but the appointments are not rendered.


Thank you!

Last Updated: 20 Oct 2023 14:01 by ADMIN

When the VisualizationLayer is populated with FrameworkElement objects (often through the ItemTemplate) and the MapLayer.Location value of a FrameworkElement is updated at runtime, the element itself is not moved to the new location. This happens only if the FrameworkElement is outside of the viewport during the location change action.

To work this around, on location change, remove the data element from the ItemsSource and add it again.

Last Updated: 18 Sep 2023 08:52 by ADMIN
Created by: Devel
Comments: 5
Category: UI for WPF
Type: Bug Report



I want to report a bug with text color in textbox and presumably in some other controls. When the textbox is edited, then the color is correctly black:

Telerik:   Windows 11 settings textBox: 

But when the textbox loses focus, it changes the color to gray, which is hard to read and looks like disabled:

Telerik:  Windows 11 settings textBox: 



Last Updated: 21 Aug 2023 06:44 by ADMIN


I download the source code 'Telerik_UI_for_WPF_Source_2022_1_117' and then I want to run 'Build_WPF60.bat' [\Telerik_UI_for_WPF_Source_2022_1_117\Build\BatFiles]. An error occurs, see the attachment: 'Could not locate the assembly "Telerik.Windows.Documents.Core".' I tried it on Win 10 and Win 11 with installed VS202


Best regards
Huráb Radek

Last Updated: 14 Aug 2023 12:47 by ADMIN
Make sure all properties are rising OnPropertyChanged event.
Last Updated: 29 May 2023 15:32 by ADMIN
Created by: Telerik Admin
Comments: 2
Category: UI for WPF
Type: Feature Request
Develop  a new control - Fisheye Panel.
Last Updated: 29 May 2023 15:29 by ADMIN
Created by: Telerik Admin
Comments: 1
Category: UI for WPF
Type: Feature Request
New control request: FishEye menu.
Last Updated: 29 May 2023 15:28 by ADMIN
Created by: Telerik Admin
Comments: 1
Category: UI for WPF
Type: Feature Request
A new Tag Cloud control similar to the WinForms and ASP.NET Ajax counterparts (
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