RadMessageBox(form) is a telerik replacement for the System.Windows.Forms.MessageBox.

MessageBox has a parameter MessageBoxOptions.DefaultDesktopOnly which makes it (surprisingly) topmost. RadMessageBox does not have this option.

I have a scenario where the RadMessageBox is hidden by a total different application when shown. So I need to make it topmost.

Can you add some kind op RadMessageBoxOptions to make it topmost?

System.NullReferenceException: Object reference not set to an instance of an object.
   at Telerik.Windows.Pdf.Documents.Fixed.FormatProviders.Old.Pdf.PdfElementToFixedElementTranslator.CreateFormField(PdfContentManager contentManager, FormFieldNodeOld terminalFormField)
   at Telerik.Windows.Pdf.Documents.Fixed.FormatProviders.Old.Pdf.PdfElementToFixedElementTranslator.CreateWidgetAnnotation(WidgetOld source, PdfFormatProvider provider)
   at Telerik.Windows.Pdf.Documents.Fixed.FormatProviders.Old.Pdf.PdfElementToFixedElementTranslator.CreateAnnotation(AnnotationOld source, PdfFormatProvider provider)
   at Telerik.Windows.Pdf.Documents.Fixed.FormatProviders.Pdf.PdfFormatProvider.CopyAnnotationsFromPageSource(PageOld source, AnnotationCollection annotations)
   at Telerik.Windows.Pdf.Documents.Fixed.FormatProviders.Pdf.PdfFormatProvider.LoadPageAnnotations(RadFixedPage page)
   at Telerik.Windows.Pdf.Documents.Fixed.Model.RadFixedPage.LoadAnnotations()
   at Telerik.Windows.Pdf.Documents.Fixed.Model.Internal.RadFixedPageInternal.Arrange()
   at Telerik.Windows.Pdf.Documents.Fixed.FormatProviders.Old.Pdf.PdfReader.PageContentLoader.Telerik.Windows.Pdf.Documents.Fixed.FormatProviders.Old.Pdf.PdfReader.IPageContentLoader.LoadPageContent(RadFixedPage page)
   at Telerik.Windows.Pdf.Documents.Fixed.FormatProviders.Old.Pdf.PdfReader.PagesCacheManager.BeginUsingPageContent(RadFixedPage page)
   at Telerik.WinControls.UI.RadFixedPageElement.Attach(RadFixedPage data, Object context)
   at Telerik.WinControls.UI.RadFixedPageElement..ctor(RadFixedPage page, RadPdfViewerElement owner)
   at Telerik.WinControls.UI.RadPdfViewerElement.CreatePageElement(RadFixedPage data, Object context)
   at Telerik.WinControls.UI.FixedPageElementProvider.CreateElement(RadFixedPage data, Object context)
   at Telerik.WinControls.UI.BaseVirtualizedElementProvider`1.GetElement(T data, Object context)
   at Telerik.WinControls.UI.BaseVirtualizedContainer`1.UpdateElement(Int32 position, T data)
   at Telerik.WinControls.UI.BaseVirtualizedContainer`1.MeasureElements()
   at Telerik.WinControls.PdfViewer.PdfViewerStackContainer.MeasureElements()
   at Telerik.WinControls.UI.BaseVirtualizedContainer`1.MeasureOverride(SizeF availableSize)
   at Telerik.WinControls.RadElement.MeasureCore(SizeF availableSize)
   at Telerik.WinControls.RadElement.Measure(SizeF availableSize)
   at Telerik.WinControls.UI.ScrollViewElement`1.MeasureViewElement(SizeF availableSize)
   at Telerik.WinControls.UI.ScrollViewElement`1.MeasureView(SizeF availableSize)
   at Telerik.WinControls.UI.ScrollViewElement`1.MeasureOverride(SizeF availableSize)
   at Telerik.WinControls.UI.VirtualizedScrollPanel`2.MeasureOverride(SizeF availableSize)
   at Telerik.WinControls.UI.RadPdfViewerElement.MeasureOverride(SizeF availableSize)
   at Telerik.WinControls.RadElement.MeasureCore(SizeF availableSize)
   at Telerik.WinControls.RadElement.Measure(SizeF availableSize)
   at Telerik.WinControls.Layouts.ContextLayoutManager.UpdateLayout()
   at Telerik.WinControls.Layouts.ContextLayoutManager.UpdateLayoutCallback(ILayoutManager manager)

Using specifically Win11 Compact DARK theme has additional space compared to the Win11 Compact LIGHT theme. See the pictures.

• On Light theme there are 4 pixels between the form border and the top border of a tab.
• On Dark theme there are 12 pixels between the form border and the top border of a tab.

In my opinion the dark theme has a wrong height here and the light theme is correct, especially compared to other themes, even Office 2019 for example.

Light theme:

Dark theme:

In the Visual Theme Builder (fresh installed Telerik UI for WinForms) you'll get an error because the directory "VbsRecoveryData" seems to be missing. Creating the directory before "package.Compress(path)" fixes this for me.

Hello,

We encountered problems with configuration of the toolbox in Visual Studio 2022 when out-of-proc designer is active.
More information about the usage and reason for the out-of-proc designer: https://github.com/dotnet/winforms/blob/main/docs/designer/designer-selection.md

Tested environment:
- Visual Studio 2022
- .NET Framework 4.7.1
- 32-bit application
- Windows 11 Pro
- Telerik UI For Winforms 2025.2.520.462

When trying to add a rad control from the toolbox the error in attachment occurs.

Workaround:
- Disable the out-of-proc designer in the project file:

<UseWinFormsOutOfProcDesigner>False</UseWinFormsOutOfProcDesigner>

 

 

 

 

At this moment, DocumenWindow has only Image property.

Contrary to Telerik.WinControls.UI.Barcode.QRCode, Telerik.WinControls.UI.Barcode.Symbology.QRCode creates invalid (unscannable) QR-Codes if the message contains umlauts when using ECIMode.UTF8.

 

We are using Symbology.QRCode, because we use it in columns of a RadGridView.

I've attached two example QR-Codes of the value "Bär", one using Barcode.QRCode, and the other one using Barcode.Symbology.QRCode.

Note: I have one scanner that can scan some of the Barcode.Symbology QR-Codes with umlauts.

(This request may be specific to VS solutions which produce only DLLs, and not to ones which create a .exe.)

At the moment, the default behaviour for everything else in my VS project is to not produce warnings unless something might be wrong, which I may need to action.

WinForms,as of the latest release (2025) is the only thing which produces warning messages where there is not problem, which is not very tidy. I only want to see things in the build output which need my attention, defintely not 'happy' messages, or warnings which are not needed.

Currently, for each project in my solution, I get a message like:

1>  [Telerik and Kendo UI Licensing]
1>        Valid Telerik UI for WinForms license found. Make sure the main application also references Telerik.Licensing when using a class library.

...but I have a valid licence, and everything is OK. No action is needed.

Your support suggested adding...

  <TelerikLicensingVerbosity>quiet</TelerikLicensingVerbosity>

...to each project in my solution, but that still produces the above build message.

A polite solution would be to turn-off ALL such warning messages, and let me switch them ON when needed. Preferably via a setting somewhere, not by editing the VS project file, which means unloading, editing the project file, and realoading each of many  projects.

(Visual Studio 2026, not currently an option in the drop-down below)

There is a big problem with Telerik controls when using national resource files.  Switching from one language to another and again sometimes destroys the user interface. It especially concerns RadCheckBox control. Text, tooltip and probably other properties from one control appear in other control etc. I think it can be a general problem because I also noticed that sometimes Image from one RadButton control appears in other button.

I prepared a set of images which show how it happended in my case. Switching from Default language to Polish language and again and then adding and removing new RadCheckBox completly destroyed user interface in my sample UserControl. This new RadCheckbox was created as a copy of existing RadCheckBox what may be a clue.

I also attached VS2019 project with my sample UserControl.

 

Best regards,

Andrzej

Team,

we did not get any help from public forums, 

we are expecting in 2026Q1,

so please handle it, https://feedback.telerik.com/winforms/1700973-radfiledialogs-selecting-large-number-of-files-is-very-slow

Team,

 

we did not get any help from public forum,

 

we are expecting in 2026 Q1,

RadControl: Incorrect Font scaling after DPI switch runtime

team,

 

we did not get any help from public forum,

already we commited our stack holders will resolve in 2026 Q1, so please close ASAP.

 

RadFileDialogs: Selecting Large Number of Files is Very Slow

team,

 

we did not get any help from public forum,

already we commited our stack holders will resolve in 2026 Q1, so please close ASAP.

 

RadControl: Incorrect Font scaling after DPI switch runtime

NullReferenceException is called during EndUpdate() under heavy Garbage Collector activity

The content is exported correctly, but the following error occurs:

 

Hi support,

I think I found an issue with the default behavior of Telerik UI for Winforms on a HighDPI PerMonitorV2 configuration.

The application works correctly and resizes well if moved between screen with different Font Scalings.

However, if the user changes the main screen to one with a different scaling, the application is strangely taking the change into account and would also not come back to its original state.

Attached is a GIF showing the problem and the project. The application on run on screen 3 being main display at 100% FontScale. If I pass Screen 1, the main display (which is 125% font scaled), the icons of the app are made larger (for no reason), going back to screen 1 being the main screen, will not restore the icon to the correct size, unless you make parts of the application being redrawn.

I've a more related question but it's more complex and I won't be able to provide a project for this, so I'm just trying here ;) In our real application (not this test one), when setting PerMonitorV2 mode, we need to have RadControl.EnableRadAutoScale set to false for the controls to resize correctly when changing monitors whereas this [test] application needs it to be let it set to true to kind of do the same thing ?! Any idea on where the difference can come from ?

Thanks & regards,

Benjamin Foucher