In Development
Last Updated: 30 Oct 2025 12:46 by ADMIN
Exception when pasting content with a custom list style that is not font in the document.
Unplanned
Last Updated: 30 Oct 2025 12:28 by Ronen
OutOfMemoryException has thrown when creating a thumbnail with the ThumbnailFactory.

This behavior is observed with binaries version 2020.2.513 or later.
In Development
Last Updated: 30 Oct 2025 11:46 by Adriana
Scheduled for 2025 Q4 (November)
By default, when typing text in the RadSyntaxEditor and you reach the end of the viewport (horizontally or vertically), the control auto-scrolls so that the newly typed character is within the viewport. This behavior stops working after you zoom-in the editor.
Unplanned
Last Updated: 30 Oct 2025 10:26 by Dennis

RichTextBox: Bullet list with several levels is not viewed correctly in WordPad. 

In Word, this works as expected. When the document is imported into RadRichTextBox, this works as well.

Unplanned
Last Updated: 30 Oct 2025 09:53 by Philipp
TreeListView with IsReadOnly True and EnableColumnVirtualization True.
Custom column is defined in code with IsReadOnly False.
Runtime, user edits a cell from the column and then scrolls horizontally - this leads to UI freeze, endlessly.
In Development
Last Updated: 30 Oct 2025 09:24 by ADMIN

There are fragmented join geometries when drawing the joints between line segments that create very sharp angles. The fragments are presented by wrongly drawn long ray that start from the join.

This work this around, you can set the DefaultLineVisualGeometrySelector property of the LineSeries3D.

lineSeries.DefaultLineVisualGeometrySelector = new Telerik.Windows.Controls.ChartView.Geometry3DSelector();

Note that his workaround works because it removes the joints between the line segments. This prevents the origin of the problem, but it makes the line more jaggy.

Unplanned
Last Updated: 30 Oct 2025 07:02 by Marco

Hello Support,

In the daily and weekly view from the ScheduleVies, the last appointments of daily appointments that span several days are not displayed.

Our customers often have daily appointments that span several days. When they switch to the daily or weekly view, the last day of these appointments is missing. We are now receiving daily complaints that the daily and weekly views are unusable. Please fix this bug as soon as possible. This error did not exist in the old Telerik library, but unfortunately we cannot reinstall the old library.

Thank you for your efforts.

Greetings marco

In Development
Last Updated: 29 Oct 2025 16:16 by ADMIN
Scheduled for 2025 Q4 (November)

NullReferenceException thrown on opening the CompletionListWindow when RadSyntaxEditor is hosted in a non-WPF application (usually WinForms) and there are no WPF Application and MainWindow initialized. 

This can happen if the RadSyntaxEditor for WPF is hosted in a WinForms application. In this scenario the System.Windows.Application.Current and its MainWindow are not initialized, which is what the IntelliPrompt positioning logic relies on.

Exception details:

System.NullReferenceException: 'Object reference not set to an instance of an object.'
> Telerik.Windows.Controls.SyntaxEditor.dll!Telerik.Windows.Controls.SyntaxEditor.UI.IntelliPromptBase.SetPosition(System.Windows.Point pointInScreen) Line 452 C#  Telerik.Windows.Controls.SyntaxEditor.dll!Telerik.Windows.Controls.SyntaxEditor.UI.IntelliPromptBase.SetPosition(System.Windows.Point pointInEditorPresenter, System.Windows.Point pointAboveTheCaret) Line 442 C#  Telerik.Windows.Controls.SyntaxEditor.dll!Telerik.Windows.Controls.SyntaxEditor.UI.IntelliPromptBase.SetPositionInView() Line 480 C#  Telerik.Windows.Controls.SyntaxEditor.dll!Telerik.Windows.Controls.SyntaxEditor.UI.IntelliPromptBase.InitializeIntellisense() Line 401 C#  Telerik.Windows.Controls.SyntaxEditor.dll!Telerik.Windows.Controls.SyntaxEditor.UI.IntelliPromptBase.Show(Telerik.Windows.Controls.SyntaxEditor.UI.CaretPosition caretStartPosition, Telerik.Windows.Controls.SyntaxEditor.UI.CaretPosition caretEndPositions) Line 211 C#
  Telerik.Windows.Controls.SyntaxEditor.dll!Telerik.Windows.Controls.SyntaxEditor.UI.IntelliPromptBase.Show() Line 182 C#

To work this around, you can initialize a new WPF application and MainWindow and create a hidden HwndSource for the MainWindow. This should happen before showing the WPF content in the WinForms application's code. 

 public Form1()
 {
     InitializeComponent();

     new System.Windows.Application();
     System.Windows.Application.Current.MainWindow = new System.Windows.Window();

     var parameters = new HwndSourceParameters("HiddenHost")
     {
         Width = 1, Height = 1,
         WindowStyle = unchecked((int)0x80000000) // WS_POPUP | WS_EX_NOACTIVATE
     };
     var hwndSource = new HwndSource(parameters);
     hwndSource.RootVisual = System.Windows.Application.Current.MainWindow;

      // other code here

     ElementHost host = new ElementHost { Dock = DockStyle.Fill };
     host.Child = wpfControl
     this.Controls.Add(host);
 }

In Development
Last Updated: 29 Oct 2025 16:16 by ADMIN
Scheduled for 2025 Q4 (November)
When the pane tabs of a RadPaneGroup are reordered in a quick succession, a NullReferenceException is raised.
In Development
Last Updated: 29 Oct 2025 16:16 by ADMIN
Scheduled for 2025 Q4 (November)

TypeAccessException occurs in .NET Framework projects when using internal class for the data point models. The error doesn't occur in .NET 8 projects.

dsa

System.TypeAccessException: 'Attempt by method 'DynamicClass.Telerik_DynamicGetter_Argument(System.Object)' to access type 'WpfApp29.ChartPoint' failed.'
at Telerik.Windows.Controls.Chart.dll!Telerik.Windows.Controls.ChartView.PropertyNameDataPointBinding.GetValue(object instance) 	Telerik.Windows.Controls.Chart.dll!Telerik.Windows.Controls.ChartView.ScatterSeriesDataSource.InitializeBinding(Telerik.Windows.Controls.ChartView.DataPointBindingEntry binding)	Telerik.Windows.Controls.Chart.dll!Telerik.Windows.Controls.ChartView.ChartSeriesDataSource.GenerateDataPoint(object dataItem, int index) 	Telerik.Windows.Controls.Chart.dll!Telerik.Windows.Controls.ChartView.ChartSeriesDataSource.BindCore(System.Collections.IEnumerable source)
Telerik.Windows.Controls.Chart.dll!Telerik.Windows.Controls.ChartView.ChartSeriesDataSource.Bind(System.Collections.IEnumerable itemSource)
Telerik.Windows.Controls.Chart.dll!Telerik.Windows.Controls.ChartView.ChartSeriesDataSource.Rebind(System.Collections.IEnumerable oldSource, System.Collections.IEnumerable newSource, bool shouldUpdateSelectedPoints) Telerik.Windows.Controls.Chart.dll!Telerik.Windows.Controls.ChartView.ChartSeriesDataSource.ItemsSource.set(System.Collections.IEnumerable value) Telerik.Windows.Controls.Chart.dll!Telerik.Windows.Controls.ChartView.ChartSeries.InitDataBinding() Line Telerik.Windows.Controls.Chart.dll!Telerik.Windows.Controls.ChartView.ScatterPointSeries.InitDataBinding() Telerik.Windows.Controls.Chart.dll!Telerik.Windows.Controls.ChartView.ChartSeries.OnApplyTemplate() Telerik.Windows.Controls.Chart.dll!Telerik.Windows.Controls.ChartView.PointTemplateSeries.OnApplyTemplate()

To work this around, upgrade the target framework of the project to .NET 8. Or use the GenericDataPointBinding class for the binding properties of the series (XValueBinding, YValueBinding, etc.), instead of the default PropertyNameDataPointBinding.


In Development
Last Updated: 29 Oct 2025 16:16 by ADMIN
Scheduled for 2025 Q4 (November)

The RichTextBox internal logic that imports .docx documents (DocxFormatProvider) doesn't support elements that don't need direct content, but have both start and end tags. Instead such elements should use self-closing tags. 

For example, instead of <w:vertAlign w:val="baseline"></w:vertAlign> it should be <w:vertAlign w:val="baseline"/>

When such element is read during import, issues may occur. Two main known issues here are with the w:vertAlign and Relationship tags.

Using

<w:vertAlign w:val="baseline"></w:vertAlign> 

instead of

<w:vertAlign w:val="baseline"/> 

throws NullReferenceException with the following stack trace:

System.NullReferenceException: 'Object reference not set to an instance of an object.'
Telerik.Windows.Documents.FormatProviders.OpenXml.dll!Telerik.Windows.Documents.FormatProviders.OpenXml.OpenXmlHelper.ConvertStringToBaselineAlignment(string value) Line 168 C#  
Telerik.Windows.Documents.FormatProviders.OpenXml.dll!Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Import.SpanStyleImporter.ReadBaselineAlignment(Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Parsing.Style style) Line 243 C#  
Telerik.Windows.Documents.FormatProviders.OpenXml.dll!Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Import.SpanStyleImporter.ReadStyle(Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Parsing.Style style) Line 88 C#  
Telerik.Windows.Documents.FormatProviders.OpenXml.dll!Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Import.StyleDefinitionsImporter.ReadSpanStyleProperties(Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Parsing.Style style) Line 278 C#  
Telerik.Windows.Documents.FormatProviders.OpenXml.dll!Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Import.StyleDefinitionsImporter.ReadStyle() Line 188 C#  
Telerik.Windows.Documents.FormatProviders.OpenXml.dll!Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Import.StyleDefinitionsImporter.Import() Line 67 C#  
Telerik.Windows.Documents.FormatProviders.OpenXml.dll!Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Import.DocxImporter.ReadXmlContentFromPackage(Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Import.DocxPartImporterBase importer) Line 430 C#  
Telerik.Windows.Documents.FormatProviders.OpenXml.dll!Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Import.DocxImporter.ReadXmlContentAndRelationsFromPackage(Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Import.DocxPartImporterBase importer) Line 406 C#  
Telerik.Windows.Documents.FormatProviders.OpenXml.dll!Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Import.DocxImporter.Import() Line 190 C#  
Telerik.Windows.Documents.FormatProviders.OpenXml.dll!Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.DocxFormatProvider.Import(System.IO.Stream input) Line 147 C#
Telerik.Windows.Documents.dll!Telerik.Windows.Documents.FormatProviders.DocumentFormatProviderBase.Import(byte[] input) Line 90 C#

Using

<Relationship Id="rId00004" Target="styles.xml" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/styles"></Relationship> 

instead of

<Relationship Id="rId00004" Target="styles.xml" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/styles"/> 

throws KeyNotFoundException with the following stack trace:

KeyNotFoundException: The given key was not present in the dictionary.
    System.ThrowHelper.ThrowKeyNotFoundException() in ThrowHelper.cs
    System.Collections.Generic.Dictionary<TKey, TValue>.this[TKey].get(TKey) in Dictionary.cs
    Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Import.PartRelationsImporter.GetRelationByID(string) in PartRelationsImporter.cs
    Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Import.DocxImporter.GetRelationByID(string) in DocxImporter.cs
    Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Import.MainDocumentImporter.BuildSection() in MainDocumentImporter.cs
    Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Import.MainDocumentImporter.BuildBody() in MainDocumentImporter.cs
    Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Import.MainDocumentImporter.BuildDocument() in MainDocumentImporter.cs
    Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Import.MainDocumentImporter.Import() in MainDocumentImporter.cs
    Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Import.DocxImporter.ReadXmlContentFromPackage(Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Import.DocxPartImporterBase) in DocxImporter.cs
    Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Import.DocxImporter.ReadXmlContentAndRelationsFromPackage(Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.Import.DocxPartImporterBase) in DocxImporter.cs

To work this around, import the document with the WordsProcessing library. If you need to display it in RadRichTextBox, you can export it again using the WordsProcessing library. This will normalize the tags. Then import it again using the RadDocument's DocxFormatProvider.

 var dplDocxFormatProvider = new Telerik.Windows.Documents.Flow.FormatProviders.Docx.DocxFormatProvider();
 RadFlowDocument flowDocument = dplDocxFormatProvider.Import(File.ReadAllBytes("../../../test.docx"), null);

 var docBytes = dplDocxFormatProvider.Export(flowDocument, null);
 File.WriteAllBytes("../../../modified-doc.docx", docBytes);

 var rtbDocxFormatProvider= new Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.DocxFormatProvider();
 RadDocument document = rtbDocxFormatProvider.Import(File.ReadAllBytes("../../../modified-doc.docx"));

 

In Development
Last Updated: 29 Oct 2025 16:16 by ADMIN
Scheduled for 2025 Q4 (November)
When selecting multiple cells, clicking on the current active cell (which is selected) does not clear its selection but moves the active cell to one of the other cells from the selected range.
In Development
Last Updated: 29 Oct 2025 16:16 by ADMIN
Scheduled for 2025 Q4 (November)

The selection a RadComboBox hosted in RadDataForm gets cleared on commit changes. This happens when the RadComboBox is added in the EditTemplate and its IsEditable is set to True. Committing the edit clears the TextBox of the ComboBox, which clears the selection.

To work this around, subscribe to the EditEnding event of RadDataForm and clear the DataContext of the RadComboBox element.

  private void RadDataForm_EditEnding(object sender, Telerik.Windows.Controls.Data.DataForm.EditEndingEventArgs e)
  {
      var dataForm = (RadDataForm)sender;
      var myField = dataForm.ChildrenOfType<DataFormDataField>().FirstOrDefault(df => df.Name == "myField");
      if (myField != null)
      {
          var comboBox = (RadComboBox)myField.Content;
          comboBox.DataContext = null;
      }
  }

In Development
Last Updated: 29 Oct 2025 16:16 by ADMIN
Scheduled for 2025 Q4 (November)
RadVirtualKeyboard starts a new Task which constantly checks the system culture and synchronizes this with the culture of the control. When the control gets unloaded or when the SynchronizeCultureWithSystem property is set to False, the Task's thread is stopped using the Cancel method of the associated CancellationToken, along with the ThrowIfCancellationRequested method. 

This throws an OperationCanceledException, which is the expected behavior to signal that the thread was canceled. However, the exception is marked as unobserved, which throws the TaskScheduler.UnobservedTaskException static event. This doesn't cause problems in the control or the host application, but the RadVirtualKeyboard can handled it better, so the exception is not marked as unobserved.
In Development
Last Updated: 29 Oct 2025 16:16 by ADMIN
Scheduled for 2025 Q4 (November)
Having a RadTabControl in a RadPane's content, showing it in the DockingNavigator, may appear incorrectly positioned.
Unplanned
Last Updated: 29 Oct 2025 16:16 by ADMIN
Scheduled for 2025 Q4 (November)
When the culture is set to th-TH (Thai culture), an ArgumentOutOfRangeException is raised when the ItemsSource of RadGridView is rebound.
In Development
Last Updated: 29 Oct 2025 16:16 by ADMIN
Scheduled for 2025 Q4 (November)

Pressing the Enter key when a field editor is focused will scroll the vertical scrollbar to the topmost offset. This is reproducible when the properties are grouped. Also, the RenderMode should be set to Flat.

To work this around, change the RenderMode setting to Hierarchical right before the Enter key logic is executed and then return it back to Flat after some time.

private void RadPropertyGrid_PreviewKeyDown(object sender, System.Windows.Input.KeyEventArgs e)
{
    var propertyGrid = (RadPropertyGrid)sender;
    var currentMode = propertyGrid1.RenderMode;
    propertyGrid.RenderMode = RenderMode.Hierarchical;

    Dispatcher.BeginInvoke(new Action(() =>
    {
        propertyGrid.RenderMode = currentMode;
    }));
}

In Development
Last Updated: 29 Oct 2025 16:16 by ADMIN
Scheduled for 2025 Q4 (November)
Pressing the Home and End keys selects the first/last items even if they are collapsed/hidden.
In Development
Last Updated: 29 Oct 2025 16:16 by ADMIN
Scheduled for 2025 Q4 (November)

A memory leak in RadPdfViewer when the control gets removed from the visual tree.

To work this around, use the reflection API to access the leaking VisualTarget objects and call their Dispose method manually.

var pdfViewer = hostBorder.Child as RadPdfViewer;

if (pdfViewer != null)
{
    var canvas = viewer.ChildrenOfType<Canvas>().FirstOrDefault(x => x.GetType().Name.Contains("ContentElementsCanvas"));                
    var visualTargetsDictionaryField = canvas.GetType().GetField("pageNumberToVisualTarget", BindingFlags.NonPublic | BindingFlags.Instance);
    var visualTargetsDictionary = (Dictionary<int, List<VisualTarget>>)visualTargetsDictionaryField.GetValue(canvas);
    foreach (KeyValuePair<int, List<VisualTarget>> target in visualTargetsDictionary)
    {
        for (int i = 0; i < target.Value.Count; i++)
        {
            VisualTarget item = target.Value[i];
            item.RootVisual = null;
            item.Dispose();
        }
    }  
}
hostBorder.Child = null;
hostBorder.Child = new RadPdfViewer() { Document = newDocument };

In Development
Last Updated: 29 Oct 2025 16:16 by ADMIN
Scheduled for 2025 Q4 (November)

Document exported to DOCX with 2025 Q2 cannot be opened by 2025 Q1 or previous versions.

 

Workaround: Use document processing to fix the document.

var processing_provider = new Telerik.Windows.Documents.Flow.FormatProviders.Docx.DocxFormatProvider();

var document = processing_provider.Import(File.ReadAllBytes("C:\\Users\\test\\Downloads\\word1.docx"),null);
var bytes_ = processing_provider.Export(document, null);

var rtb_provider = new Telerik.Windows.Documents.FormatProviders.OpenXml.Docx.DocxFormatProvider();
var doc = rtb_provider.Import(bytes_);
radRichTextBox.Document = doc;

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