Workaround: set UseCompatibleTextRendering to true.

Overview

This repository documents a bug found in the Telerik PDF Viewer control for Windows Forms. The issue specifically affects the rendering of SVG graphics embedded in PDF files, where the stroke-width attribute is ignored by the viewer.

Affected Component

• Product: Telerik UI for WinForms
• Control: `RadPdfViewer'
• Version: 2025.01
• Platform: Windows Forms (.NET Framework)

Description of the Issue

When a PDF file contains an embedded SVG graphic that utilizes the stroke-width CSS property (or SVG attribute), the stroke width is not rendered correctly in Telerik's PDF preview control. Regardless of:

• Unit used (e.g., px, pt, em, %, etc.)
• Value assigned (e.g., stroke-width: 5, stroke-width: 30, etc.)

…the resulting line always appears thin, as if the stroke width were ignored entirely. This makes the SVG appear incorrectly and inconsistent with its rendering in other PDF viewers (e.g., Adobe Acrobat, Chrome's built-in viewer).

Steps to Reproduce

1. Run the application from provided MCVE
2. Observe the SVG lines in PDF preview: all strokes appear thin, regardless of defined stroke width.

Expected Behavior

The Telerik PDF viewer should correctly honor and render the stroke-width property defined within SVG elements embedded in the PDF file.

Actual Behavior

All strokes in SVGs appear very thin, with no visual difference despite varying stroke widths in the source SVG.

Sample Files

• ✅ _PdfExample.pdf: A PDF with SVG lines that render correctly in Microsoft Edge.
• ✅ _PdfExample.pdf: Screenshot of how the PDF file looks in Microsoft Edge.
• ❌ _ScreenshotFromTelerik.png: Screenshot of how the same file looks in the Telerik PDF Viewer (note the thin lines).
• 🔍 _LargeStroke.svg, _SmallStroke.svg: The original SVGs used in the PDF file.

Environment

Component	Version
Telerik UI	2025.1.211.48
.NET Framework	.NET Framework 4.8
OS	Windows 11

Suggested Fix

Ensure that the rendering engine used by RadPdfViewer fully supports the SVG stroke-width attribute when parsing and rendering embedded SVG content.

Visual Studio 2022 crashes when working with a solution containing two WinForms projects:

• Project 1: WinForms (.NET 9) with Telerik
• Project 2: WinForms (.NET 6) without Telerik

Steps to Reproduce:

1. Create a new solution in Visual Studio 2022.
2. Add two WinForms projects:
   • Project 1: WinForms (.NET 9) with Telerik
   • Project 2: WinForms (.NET 6) without Telerik
3. Open the WinForms designer for a form in Project 1 (Telerik, .NET 9).
4. Without closing the designer, open the WinForms designer for a form in Project 2 (.NET 6, no Telerik).
5. Switch to the code view of the form in Project 2.
6. Switch back to the WinForms designer in Project 2.

Expected Result:
Visual Studio should smoothly switch between code and designer views without issues.

Actual Result:
Visual Studio freezes and crashes after switching back to the WinForms designer in Project 2.

Environment:

• Visual Studio 2022
• Windows Version: (Windows 11 x64)
• Telerik WinForms Version: (2025.1.211)

Additional Notes:

• The issue seems to be related to handling different .NET versions and Telerik components in the same solution.
• The crash occurs consistently when following the steps above.
• No explicit error messages are shown before Visual Studio closes.

---

This behavior is related to how the control is measured while using the MS Form. In the given scenario, the control has many columns, and some of them are pinned. Moving to the last column and typing in the filter cell will filter the rows in the column. However, when filtering, if the row number is less than the viewport, the vertical scrollbar will disappear as it is not needed anymore, and the filter editor will be placed in the wrong column. This will mess with the filter cell editor. 

In the current scenario, when clicking on the checkbox inside a GridViewCheckBoxColumn, the CellBeginEdit event will be called. If we cancel the event by setting the Cancel property to true, the CellBeginEdit will be called twice.

Implement UIAutomation.

ImageKey is cleared when moving a node from one treeview to another and disposing the first.

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)

 

The problem is, that the "Activated" sub of another form was fired after the overlay was closed.

After a hyperlink is edited in a RTF document it duplicated

For example, if you choose to print second page like this: 

It prints only the first page of the document, instead of the second page.

In the following scenario, we have enabled the pager functionality of the control. If we move to a different page and then set the DataSource to Null, the page index will not be reset. 

Hello team!

I've found a misbehavior on RadForm when setting the size.

When you set the Size of the Form before it actually has shown then it will do some re-calculation, change the form size several times, and ending up in a too big size. The behavior is different to a original Form and that's why I'd treat this as bug.

The first screenshot shows a RadForm that set itself to ClientSize = 500; 500 on the constructor, like usual. It ends up in a size slightly bigger then defined.


This second screenshot shows a RadForm that set itself to ClientSize on "Shown". It ends up in having the correct size.

Whenever you set a breakpoint to the method "Form1_Resize" you can capture that the first time the Size of the RadForm get changed is our "ClientSize = new Size(500, 500)". Then the Size get changed two times by RadForm itself to something slightly smaller. Lastly the Size get changed by RadForm another time, but this time slightly bigger

This behaviors can lead to inconsistent UI size, e. .g small spaces when using AutoSize = true in certain cases. But yet didn't figured completely out when exactly it happens, just that it comes from this slightly increased Size of RadForm.

Can you please take a look to it and, if it is one, report it as bug?

Thank you very much!

Regards,
Pascal

The control allows you to scroll the view while dragging and appointment. In a case when the appointment is at the bottom of the view and we try to move it above, the view will scroll to see the top cells. When the mouse is above the column header cells, the scroll stops. This could be improved.

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?

The EnableHotTracking property works only in the first level hierarchy. The lower levels still get highlighted.

The StepClicked event should trigger when a RadStepProgressBarItem is clicked.