Last Updated: 15 Jul 2020 05:14 by ADMIN
Created by: Pim
Comments: 1
Category: UI for WinForms
Type: Bug Report

Submitted on customer behalf:


We are currently using version 2017.3.1017.40 and noticed an issue with the display of the RadSplitButtonElement in combination with the theme Office2010Blue.
When we disable the RadSplitButtonElement, or more precisely the ActionButtonElement in the DropDownEditorLayoutPanel, it does not display as disabled in the Office2010Blue theme.
In other themes (e.g. Office2010Silver) it does show as disabled.

When trying the latest version (2020.2.616.40) we still get this behaviour, see example below:


It appears similar to the issue mentioned in https://feedback.telerik.com/winforms/1370576-fix-radcommandbar-some-of-the-elements-in-the-control-are-not-rendered-as-disabled-with-office2010blue-and-office2010black-themes

Last Updated: 07 Jul 2020 13:49 by ADMIN

UI for WinForms - Latest version.

RadRibbonBarBackstageView - Edit UI Elements


Click the … button and select your image.


To REMOVE this image you SHOULD be able to do the following:

click on the property BackgroundImage which should highlight the image-string completely.

click delete.


What you HAVE to do is this: 

click on the property BackgroundImage.

click delete.

BEFORE YOU LEAVE THIS PROPERTY you have to click the … box

Once the box opens you have to click "Cancel"


Right below this property is BackgroundImageLayout - set to "Center"

There's a dropdown arrow presumably to allow you to change the layout but nothing happens when you click it.


*Missing Property?*

Whatever image you place in this control it gets stretched and there doesn't appear to be any way to avoid this:

place an image.

run the winforms ap.

set the main form in normal mode (not maximized) and resize the height.

Your image will stretch, shrink...this is not a UI property that should be presumed.  We should be able to set None, Tile, Center, Stretch or Zoom.


Still *LOVE* your products :)

Kindest regards,

Curtis Smith 

Last Updated: 15 Jun 2020 09:09 by ADMIN
Release R2 2020 SP1

Please refer to the attached sample project:


        Me.RadImageButtonElement1.ButtonFillElement.GradientStyle = GradientStyles.Solid
        Me.RadImageButtonElement1.ShowBorder = False

Last Updated: 12 Jun 2020 16:02 by ADMIN
Release R2 2020 SP1

Just add an image in the editor and try to click on it

private void radButton1_Click(object sender, EventArgs e)
    this.radMarkupDialog1.Editor.Value = @"<img src=C:\Users\admin\Desktop\sample.jpeg />";
Last Updated: 11 Jun 2020 13:37 by ADMIN

If you have two RadGridView controls and you want to export both of the grids to a common file on two different sheets, it is suitable to use FileExportMode.NewSheetInExistingFile. However, when using the export overload to a stream doesn't respect the ExportMode.

Workaround: use exporting to a file:

            string exportFile = @"..\..\exportedData.xlsx";
            GridViewSpreadStreamExport spreadStreamExport = new GridViewSpreadStreamExport(this.radGridView1);
            spreadStreamExport.FileExportMode = FileExportMode.NewSheetInExistingFile;
            spreadStreamExport.ExportVisualSettings = false;
            spreadStreamExport.RunExport(exportFile, new SpreadStreamExportRenderer());


Under Review
Last Updated: 11 Jun 2020 09:12 by ADMIN
Created by: Robyn
Comments: 1
Category: UI for WinForms
Type: Bug Report

Hi there,


We have recently found a bug on both the RadDocument and Rad Rich Text Editor. Created a RTF document via the RadRichText Editor. The RTF document contains a table. When the document is saved and loaded from the same form, it is displaying correctly, however when loaded from a different form, it seems to have shrunk and lost the column width, thus having long and skinny columns.

We have set the fixed column width on the table, however this did not seem to solve the issue.

I have attached two screenshots for reference. One with the correct looking table, and one with the long and skinny columns.

Is there a workaround, or is this a known bug?


Correct table:



Long and skinny columns:


Currently on Telerik Winforms version 2018.3.1016.40


Kind regards,



Last Updated: 10 Jun 2020 10:19 by ADMIN
Release R2 2020 SP1


I have menu problem:

When the Backstage Button Item is clicked and you don't release a left mouse button click but instead mouse is dragged to the right of the form, Backstage Button Item stay selected and can only be returned to default state if you click on it again else its stays blue and locked.

Picture 1.

Left click, hold and drag to the right. This state can be done to all buttons see Picture 2. Focus on "MouseDown" Event is not working.

Picture 2.


My question is can this behavior be prevented ?


Thanks in advance !



Last Updated: 09 Jun 2020 16:53 by ADMIN
Release R2 2020 SP1

Hi Telerik Team,


I tried to copy and past the sourcecode from one of your demo applications (not using the copy source button!). 

Unfortunaly every time I want to copy the "<" character it skips the rest of the line.

The problem occurs on different code examples.


I know there is a "Copy source" button but sometimes you just want to copy a small part.


A screenshot of an example is attached.


Demo Application - Telerik UI for WinForms R2 2020




Last Updated: 03 Jun 2020 16:31 by ADMIN
Release R2 2020 SP1 (LIB 2020_2_603)

merging only these assembly still the icons are not visible in Spreadsheet ribbon menu

C:\Program Files (x86)\Microsoft\ILMerge\ILMerge.exe" /allowdup /target:SymphonyMESUtil.exe  /targetplatform:"v4, C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.1" /out:Merge\SymphonyMESUtil.exe ^
SymphonyMESUtil.exe ^
Telerik.WinControls.dll ^
Telerik.WinControls.UI.dll ^
TelerikCommon.dll ^
Telerik.WinControls.GridView.dll ^
Telerik.Windows.Documents.Spreadsheet.FormatProviders.OpenXml.dll ^
Telerik.Windows.Documents.Spreadsheet.FormatProviders.Pdf.dll ^
Telerik.Windows.Documents.Spreadsheet.dll ^
Telerik.WinControls.RadSpreadsheet.dll ^
Telerik.Windows.Documents.Core.dll ^

Last Updated: 03 Jun 2020 16:31 by ADMIN
Release R2 2020 SP1 (LIB 2020_2_603)

Dear Support,

I want to use the new feature - Support for SVG.

Then I have to load the file with RadSvgImage.FromFile().

I get the following exception:

System.Xml.XmlException: 'External DTD subset cannot be resolved - public ID =' - // W3C // DTD SVG 1.1 // EN ', system ID =' http://www.w3.org/Graphics/ SVG / 1.1 / DTD / svg11.dtd '.'

(Translated from German)

Problem is line 2, where the DTD is given.

Is there a way to tell XmlSerializer to ignore the validation?

Last Updated: 25 May 2020 04:41 by ADMIN

An error occur when i used .Import method on large .pdf files (> 1000 ko) with an Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.PdfFormatProvider object.


Message is:

"Impossible d'effectuer un cast d'un objet de type 'Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Types.PdfDictionary' en type 'Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Types.PdfInt'." 

There is no bug for smaller pdf files. 


Thank you 

Last Updated: 04 May 2020 11:53 by ADMIN
Release R2 2020



  • Open the VisualStudio2012Light.tssp using UI WinForms Visual Style Builder.
  • Select on RadButtonElement and Element state is ButtonFill. Double click on NormalFill repository, below is the error (attached the snapshot) -

object reference not set to an instance of an object



  • How to resolve this issue.
  • How to trace log if any.




Last Updated: 28 Apr 2020 11:18 by ADMIN

1. Set the DPI of your main monitor to 150% and the DPI of your secondary monitor to 100%.

2. Start your main form containing RadDataEntry on your secondary monitor.

You will see that that hosted controls inside RadDataEntry are not scaled correctly.



Start your main form on your secondary monitor inside OnShown event.

protected override void OnShown(EventArgs e)

    this.Location = new Point(-800, 100);


Last Updated: 27 Apr 2020 07:46 by ADMIN
Release R2 2020

Please refer to the following code snippet and follow the steps in the attached gif file:


        Dim dt As New DataTable
        dt.Columns.Add("Id", GetType(Integer))
        dt.Columns.Add("Name", GetType(String))
        For index = 1 To 10
            dt.Rows.Add(index, "Data" & index & Guid.NewGuid().ToString())
        Me.RadMultiColumnComboBox1.DataSource = dt
        Me.RadMultiColumnComboBox1.DisplayMember = "Name"
        Me.RadMultiColumnComboBox1.ValueMember = "Id"
        Me.RadMultiColumnComboBox1.AutoSizeDropDownToBestFit = True


AddHandler Me.RadMultiColumnComboBox1.DropDownOpened, AddressOf RadMultiColumnComboBox_DropDownOpened

    Private Sub RadMultiColumnComboBox_DropDownOpened(sender As Object, e As EventArgs)
        Me.RadMultiColumnComboBox1.EditorControl.HorizontalScrollState = ScrollState.AutoHide
    End Sub

Last Updated: 23 Apr 2020 16:12 by ADMIN
Release R2 2020 (LIB 2020.1.423)

Populate a RadGridView with data, move the form to a monitor with greater than 100% DPI scaling. Save the layout and then load it again. You will notice that the columns' width is increased each time.


    Sub New()
        RadControl.EnableDpiScaling = False
    End Sub
Last Updated: 23 Apr 2020 16:12 by ADMIN
Release R2 2020 (LIB 2020.1.423)
Created by: Mark
Comments: 2
Category: UI for WinForms
Type: Bug Report

Please run the attached sample project and refer to the attached gif file.


        private void RadForm1_Load(object sender, EventArgs e)
            this.Size = new Size(this.Width+1,this.Height);
            this.Size = new Size(this.Width - 1, this.Height);

Last Updated: 23 Apr 2020 16:11 by ADMIN
Release R2 2020 (LIB 2020.1.423)

Please follow the steps:

1. Create a brand new project with a ShapedForm

2. Set the BackColor property to Red and save the form.

3. Open the ThemeName drop down and close it. You will notice that the BackColor is lost since the ThemeName is serialized as empty string in the designer file.

Workaround: delete the serialized ThemeName property with empty value.

Last Updated: 23 Apr 2020 15:34 by ADMIN
Created by: Tinus
Comments: 0
Category: UI for WinForms
Type: Bug Report

1. Set HDPI on your monitor (for example 150%)

2. Set RadDataEntry data source in RunTime

You will see that RadDataEntry hosted controls are not scaled correctly.

Note that there is a related problem if the data source is set in design time. Controls themselves will be scaled correctly, however, text box hosted control's High will not be scaled correctly.

You can subscribe to ItemInitializing event before you set the DataSource and proceed by scaling RadDataEntry hosted controls manually as shown in the following code snipped.

private void radButton1_Click(object sender, EventArgs e)
    this.radDataEntry1.ItemInitializing += RadDataEntry1_ItemInitializing;
    this.radDataEntry1.ItemDefaultSize = new Size(200, 26);

    radDataEntry1.DataSource = new Employee
        FirstName = "Sarah",
        LastName = "Blake",
        Occupation = "Supplied Manager",
        StartingDate = new DateTime(2005, 04, 12),
        IsMarried = true,
        Salary = 3500,
        Gender = Gender.Female
private void RadDataEntry1_ItemInitializing(object sender, ItemInitializingEventArgs e)
    if (this.radDataEntry1.RootElement.DpiScaleFactor.Width != 1)
        foreach (Control control in e.Panel.Controls)

Last Updated: 14 Apr 2020 15:26 by ADMIN

Please refer to the attached sample project and gif file. The ShouldCheckDataRows property of the column is disabled. Hence, the developer will manage the toggle state of the data cells.

There are two problems here:

1. In the HeaderCellToggleStateChanged event we toggle all data rows in correspondence with the header checkbox. Once a data cell value is changed, we set the GridViewCheckBoxColumn.Checked property to Off. However, it is not respected and the header checkbox still remains toggle.

2. Once you scroll the columns horizontally, the header checkbox synchronizes with the value of the GridViewCheckBoxColumn.Checked property. However, all of a sudden the HeaderCellToggleStateChanged event is toggled again even though we didn't clicked the checkbox in the header at all. This will make all data cells unchecked due to the code in the HeaderCellToggleStateChanged event.

Last Updated: 09 Apr 2020 08:53 by ADMIN
Release R2 2020 (LIB 2020.1.413)

Please refer to the attached gif file.


        private void Form1_Load(object sender, EventArgs e)
            Image currentImage = this.PropertiesGrid.TableElement.CurrentRowHeaderImage;
            this.PropertiesGrid.TableElement.CurrentRowHeaderImage = new Bitmap(currentImage, currentImage.Width - 5, currentImage.Height - 5);

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