Telerik UI for Winforms

Release History

UI for WinForms R3 2020 (version 2020.3.915)

September 16, 2020

What's New

  • RadTaskDialog - new component that is a themable alternative to the windows dialog box. The dialog box is a window that allows users to perform a command, ask the users a question, provide users with information or indicate the progress of an ongoing task.
  • AutoSizeColumnMode functionality added to RadListView - it provides a way to change the columns Width automatically, allowing you to Fill the available space in the control.
  • Vector images in FluentTheme - the theme is loaded with a set of SVG images by default.
  • Brand new set of SVG images in all themes for ribbon bars of the following controls - RadRichTextEditor, RadSpreadsheet, RadDiagram and PdfViewerNavigator.
  • Create New Project templates - now available for .NET Core 3.1 and .NET 5.0.
  • .NET Core distribution options - when you create a new WinForms project for .Net Core, you can choose if you want to have your distributions as Telerik WinForms assemblies or as Telerik package references.

Support and Compatibility

  • Designer Support for .NET 5.0 Preview - Drag and drop all Telerik UI for WinForms controls in your form and use the Windows Forms Designer as you would in the full .NET framework.
  • Design Time support for the full .NET framework and .NET 5.0 - available with installation of the latest NuGet release. There is no need of installation via MSI.


  • Setting min/max size of the drop down doesn't allow decreasing the height less than the DropDownMaxSize's height.


  • Exception in the OrgChart example when using the TipOverTree layout of the OrgTreeRouter.


  • Application crashes when dropping the form just on the border between two monitors with different DPI scaling.


  • Autocomplete stops working.


  • Incorrect behavior in SelectedValue simple binding scenario.
  • The dropdown should not be closed when clicking the Excel-like filter popup in the grid.
  • When there are two rows the DropDown is sized correctly only the first time it is opened.
  • AutoSizeDropDownToBestFit is not working.
  • Wrong item is selected when the control loses the focus.
  • DropDown doesn't close always upon selection.


  • Vertical scroll bar is stuck when you start the multiple selection from the row header and move the cursor down.
  • CompositeDataFilterForm button out of bounds.
  • Missing bottom border in metro themes.
  • Self referencing hierarchy grid with Excel filters throws NullReferenceException when checkbox filter is turned off and column is sorted.
  • When grid is grouped hidden SummaryRows are not exported in Excel.
  • Error in RadListFilterPopup when using / with Brazil language.
  • When using ControlDefault theme filter icons do not get highlighted upon setting filter.
  • On the GridViewComboBoxColumn how do I prevent the drop down from covering the input cell when grid is at the bottom of the screen's viewable area.
  • In hierarchy grid CurrentViewChanged event is not triggered when select a tab which has RowsCount = 0.


  • Map Layers are not updated when IsVisible is set to false.


  • Right anchor controls (Labels, Textboxes) change their location after re-opening the form in the designer.


  • Add support for nested PropertyNames to validate Text Length.


  • Image is not properly resized via the Image Editor Dialog.


  • The NodeDataBound event is not firing when binding to a DataTable.
  • NodeMouseClick and NodeMouseDoubleClick events does not have original MouseEventsArgs.


  • SvgImage property is missing in RadListDataItems.


  • Position of the new item selector moves to front of the commandBarStripelement.
  • CommandBarDropDownList ToolTipText is always the text of the first item in the list.


  • New property: MouseWheelScrollStep.
  • Mouse Scroll does not work until you click around the tiles.


  • Setting radPopupEditor.Visible = false in the RadForm's constructor makes the associated radPopupContainer visible.


  • Incorect disabled state of the RadSplitButtonElement in Office2010Blue.


  • You cannot set Font to a RadCheckBox when using Fluent theme.


  • OS command injection vulnerabilities could be made.


  • COMException thrown when copying content from the control.


  • Setting IsReadOnly property to false does not work, allowing delete and copy paste operations.
  • OverloadListWindow/CompletionListWindow does not open at proper location.
  • XmlFoldingtagger throws an exception on not well-formed Xml.
  • When you have RadSyntaxEditor in RadForm and AcceptButton Enter key does not result in new line instead the form gets closed.
  • Changing the OverloadInfoCollection doesn't update the UI.


  • The ItemSizeMode and ItemSize properties are not working if they are set in the form`s constructor.


  • Disable copy/cut when UseSystemPasswordChar is true.
  • Typo in RadTextBoxControlElement - ContextMenuOpening.


  • Recent telerik update changed simplified layout of virtual keyboard.


  • Add a method for saving the document to a stream.
  • Implemented support for documents with startxref and its offset defined on the same line.
  • Introduced support for GBK-EUC-H encoding type of Type0Fonts.
  • Introduced support for UniGB-UTF16-H CMap encoding.
  • The editor for the text field should use the same font when editing.
  • Document's file stream is locked after saving it.
  • KeyNotFoundException is thrown while importing document because of the inability to find glyph "middot" data in Type1Font.
  • NullReferenceException is thrown when importing a document with AcroForm referencing a missing PDF object.
  • ArgumentNullException is thrown in PdfElementToFixedElementTranslator.CreateDestination.
  • CIDFont glyph widths are not imported when defined with an indirect reference which leads to incorrect character positioning.
  • Data of inline image cannot be parsed when the stream contains "ei" resulting in blank pages.
  • Incorrect text stroke width when TextMatrix scales the glyph geometry.
  • The stroke is not rendered when the text is in XForm.
  • Widgets are misplaced when the CropBox has offsets different than 0.
  • Documents are now imported with the PdfProcessing model. Use the PdfProcessing API instead. PdfDocumentSource constructors: PdfDocumentSource(Uri uri, PdfImportSettings settings) PdfDocumentSource(Stream stream, PdfImportSettings settings) PdfFormatProvider constructor: PdfFormatProvider() PdfFormatProvider Import method: RadFixedDocument Import(Stream input)


  • Exposed API allowing customers to set an annotation as word separator and to exclude it from spell checking.
  • Introduced partial support for shapes. Currently import/export is supported. With the future releases we plan to introduce: - Visualization of shapes in RTB - Create and edit shapes through the UI - Export to PDF and other formats as image
  • Import and export documents now preserve shapes. Possibilities for working with shapes and visualizing them in the control will be added in next releases.
  • Exception is thrown when exporting an HTML document to pdf.
  • Content is duplicated and not committed when pressing Space key while typing in Japanese.
  • Тhe text content of a paragraph when copy-pasting a Chinese text wrapped in a bookmark is duplicated.
  • Half-width space is inserted twice when using Japanese IME.
  • NullReferenceException is thrown when undoing font size changes in a table containing a single cell.
  • Pressing Space or Enter while using Korean IME duplicates the last character.


  • The import can now handle startxref keyword and its offset defined on the same line.
  • Introduced support for Identity-V CMap.
  • Introduced support for UniCNS-UCS2-H encoding type of Type0Fonts.
  • Data of inline image cannot be parsed when the stream contains "ei".
  • KeyNotFoundException is thrown while importing document because of the inability to find glyph "middot" data in Type1Font.
  • NotSupportedColorSpaceException is thrown when importing color space defined as an external resource.
  • NotSupportedException is thrown when importing document containing Annotation with not supported Action.
  • NullReferenceException is thrown when importing a PDF document containing InlineImage with missing parameters.
  • System.ArgumentException is thrown when setting a password to a document with form fields.
  • UriFormatException is thrown when importing UriAction with invalid URI.
  • InvalidCastException is thrown when importing predefined ToUnicode CMap.
  • NotSupportedException is thrown when trying to convert not supported Encoding Name.
  • The checkbox state is not correctly imported when the value is not specified.


  • Introduced XLS Format Provider that handles import and export of XLS documents in SpreadProcessing library.
  • Implemented text orientation for cell content.
  • Exception is thrown when the sheet name contains a single letter.
  • PrintArea is not taken into consideration when calculating the actual ScaleFactor.
  • A specific formula returns wrong result (=A1=FALSE).


  • ArgumentException when importing RTF document which has a font size set to zero.
  • NullReferenceException is thrown while importing DOCX containing shape without an id attribute.
  • PdfFormatProvider: Font properties set from CharacterFormatting are not taken into account when inserting PAGE field.
  • Table and table cell borders are not evaluated according to inheritance and conflict resolution rules.
  • XmlException is thrown when importing document with docx AltChunk element.

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