Last Updated: 27 Sep 2023 14:44 by ADMIN
Release 4.6.0 (11 Oct 2023) (R3 2023)

Using the following configuration does not produce the expected result:


        <GridPopupEditFormSettings ButtonsLayout="FormButtonsLayout.Center"/>


The button layout is always left no matter what you choose.




Possible workarounds for the time being are to position the buttons with CSS or use a Popup Buttons Template.

Last Updated: 27 Sep 2023 11:53 by Patrick

When you click on a cell which has an Editor Template with a NumericTextBox the text inside does not always get selected/highlighted. This is observed only in Server type applications. 


1. Copy the code from this REPL into a Server side project or directly download the attached Sample Project.
3. Tab in and out of the Count column.
4. The NumericTextBox does not always select the number inside.
5. [Video Example]( 


The NumericTextBox does not always select/highlight the number inside


The NumericTextBox always select/highlight the number inside
Last Updated: 27 Sep 2023 10:59 by Beverley
Created by: Naveed
Comments: 5
Category: MultiSelect
Type: Feature Request

Like and so the user can input tags on their own without them being in the app data source.



The following sample may be useful in implementing this in the meantime:


Last Updated: 27 Sep 2023 10:30 by ADMIN
Release 4.6.0 (11 Oct 2023) (R3 2023)

Currently, if the ReadOnly parameter value is set to 'true,' the user can modify the value of the DateInput by using the arrow keys.



Last Updated: 27 Sep 2023 09:17 by Mark
Created by: Fairoz
Comments: 3
Category: Charts
Type: Feature Request

I want horizontal and vertical lines in the chart to act as markers (limits, thresholds). It would be awesome if there was a way to simply draw a horizontal and vertical lines, bound to a collection of y and x data respectively.

Something like the below would be nice 

            <ChartSeries Type="@ChartSeriesType.Line" Name="@P_Name1" Color="blue"
                <ChartSeriesLabels Visible="true" Template="#=dataItem.P_Description#" />
                <ChartSeriesMarkers Size="4" />
            <ChartHorizontalLines Data="@YLinesData"/>
            <ChartVerticalLines Data="@XLinesData"/>


List<double> YLinesData, XLinesData;




You can find some more details and ideas for workarounds here to consider in the meantime.


Last Updated: 27 Sep 2023 08:53 by Hannes
We need to set a custom hint conditionally in the file select/upload drop zone, is there a solution for that?
Last Updated: 26 Sep 2023 13:14 by ADMIN

If you are zooming a page containing a DateTimePicker with "AdaptiveMode" set to "AdaptiveMode.Auto", the application crashes occasionally with the error:

Microsoft.JSInterop.JSException: Cannot read properties of null (reading 'addEventListener')
TypeError: Cannot read properties of null (reading 'addEventListener')

The more adaptive DateTimePicker instances the page contains, the more likely the error is to occur.



Last Updated: 26 Sep 2023 11:50 by ADMIN
Release 4.6.0 (11 Oct 2023) (R3 2023)
Created by: Ben
Comments: 0
Category: Editor
Type: Bug Report

The TelerikEditor demos all show bind-Value being used to marshal HTML in and out of the editor:

<TelerikEditor @bind-Value="@TheEditorValue" Width="650px" Height="400px"></TelerikEditor>

However, this causes problems - the underlying ProseMirror component emits it's own HTML (e.g. for image drag handles), which is visible in the bound Value property.

We need to be able to export "clean" HTML from the viewer, otherwise we end up saving this superflous HTML as part of our document.


This REPL shows the issue:

@page "/editor/tools"

@using Telerik.Blazor.Components.Editor 

<TelerikEditor Tools="@EditorToolSets.All"

<pre style="white-space: pre-wrap;">@Value</pre>

@code {
    public string Value { get; set; } =
        "<img src=\"img/toolbar-assets/repl-logo.svg\" />";

Steps to Reproduce

1. Open the REPL and click "Run" - observe that the bound HTML is simply

<img src="img/toolbar-assets/repl-logo.svg" />

2. Click on the Telerik logo image inside the editor - observe that the bound HTML is now

<p><img src="img/toolbar-assets/repl-logo.svg" contenteditable="false" draggable="true" class="ProseMirror-selectednode"><div class="k-editor-resize-handles-wrapper ProseMirror-widget" style="width: 857px; height: 78px; top: 8px; left: 8px;" contenteditable="false"><div class="k-editor-resize-handle southeast" data-dir-image-resize="southeast"></div><div class="k-editor-resize-handle east" data-dir-image-resize="east"></div><div class="k-editor-resize-handle south" data-dir-image-resize="south"></div><div class="k-editor-resize-handle north" data-dir-image-resize="north"></div><div class="k-editor-resize-handle west" data-dir-image-resize="west"></div><div class="k-editor-resize-handle southwest" data-dir-image-resize="southwest"></div><div class="k-editor-resize-handle northwest" data-dir-image-resize="northwest"></div><div class="k-editor-resize-handle northeast" data-dir-image-resize="northeast"></div></div><br class="ProseMirror-trailingBreak"></p>

3. Deselect the image - observe that the bound HTML no longer contains the image handles etc, but is still more verbose than when we started

<p><img src="img/toolbar-assets/repl-logo.svg" contenteditable="false" draggable="true" class=""><br class="ProseMirror-trailingBreak"></p>

4. At any point during the above steps, click the "View HTML" button in the Editor toolbar - observe that it is able to present a "clean" structure which contains no ProseMirror markup etc.


How do we access this HTML via the TelerikEditor Blazor APIs?


Last Updated: 26 Sep 2023 08:50 by ADMIN
Scheduled for 2024 R1 - PI 1 (08.11.2023) SP1

Steps To Reproduce

  1. Install a Telerik VS extension in Visual Studio 2019/2022 on a machine with high DPI scaling (more than 150%)
  2. Try to create a new Telerik application

Expected result:

The Create New Project wizard (or any other used Telerik wizard) is shown and usable as expected.

Actual result:

The Create New Project wizard is hidden or inaccessible and the project creation is blocked.

Last Updated: 25 Sep 2023 14:27 by Constantinos Petridis

I have a ComboBox/DropDownList that gets data from a remote service, using virtualization. When the PageSize property is big enough (in my case 20), I have issues scrolling up the selection box dropdown list. I'm trying to scroll but then resets to the currently selected item making it almost impossible to scroll up. You can use your own demo examples to replicate this issue.

To reproduce the issue, try the ComboBox - Virtualization, in Telerik REPL (Demo), change the PageSize from 10 to 20. Open the dropdown and select an item. Then, open again the dropdown and scroll slowly up.

Last Updated: 25 Sep 2023 11:47 by ADMIN
Created by: Taarti
Comments: 0
Category: Grid
Type: Bug Report
NVDA is not narrating Name and narrating selected value twice for the dropdowns which are present in the 'Filter' dialog in column headers.
Last Updated: 25 Sep 2023 06:06 by ADMIN
Scheduled for 4.7.0 (22 Nov 2023) (R1 PI1)

I would like to use the new structs that are part of .NET6 - the DateOnly and TimeOnly. 

Their support should extend to all respective date and time pickers and more complex components like the Grid, Gantt, Scheduler, and other applicable components. 

Last Updated: 22 Sep 2023 15:16 by ADMIN
Release 4.6.0 (11 Oct 2023) (R3 2023)

The Splitter separator has role="separator" attribute. When such a role is set and the separator is focusable, it is required that aria-valuenow attribute is also set. Currently, the Splitter separator does not have such an attribute.

From our point of view, the expected result is - NVDA / Narrator should announce separator value with respect to the position value for the separator (or no separator value at all).

Need More Info
Last Updated: 22 Sep 2023 14:35 by ADMIN

Since upgrading from 3.8 to 4.4 (including all new css) created dialogs from DialogFactory are sometimes behind an already opened modal window.
The reason for this seems to be an incorrectly, automatically calculated z-index of 10003 when the open dialog has 10006.
This does not always happen, there are scenarios where the first created dialog works fine, and the next called in the same method suddenly is behind the dialog, thus the error seems to be in telerik and not our side.

We could not yet find a proper workaround apart from creating custom dialogs.

Last Updated: 22 Sep 2023 11:22 by Thomas
Created by: Simon
Comments: 2
Category: PDFViewer
Type: Bug Report


i want to Render PDF Files with the PDF Viewer Component.

The Data of the PDF is already fetched from the API when the PDF-Viewer starts Rendering the Loading animation appears and freezes.

After a few Seconds the PDF will be Rendered.

The size of the PDF File is about 5MB.



Last Updated: 22 Sep 2023 11:08 by ADMIN
Created by: Sebastian
Comments: 1
Category: Grid
Type: Bug Report
When grid is grouped by one column and LoadGroupsOnDemand is set to true clicking 2nd group before the first one is finished loading results in an exception. It can be reproduced here: Telerik REPL for Blazor - The best place to play, experiment, share & learn using Blazor. (group only by single column).
Last Updated: 21 Sep 2023 08:13 by ADMIN

One really nice feature MudBlazor UI has is the Dialog component. You can pass a component to the Dialog Service and it will display it in a modal dialog.

Existing Example

An example of this would be:

             var orderParams = new DialogParameters();
                orderParams.Add("SelectedOrderHeader", Item);
                orderParams.Add("EditMode", "Add");
                orderParams.Add("SelectedOrderDetail", new OMSOrderDetail());
                DialogService.Show<OrdersDetailForm>("Click on orders grid to continue", orderParams);


<OrderDetailsForm> is a custom Blazor component.

Does the Telerik Blazor dev team have any plans for implementing something like this?

Last Updated: 20 Sep 2023 15:29 by ADMIN
When creating an appointment, the Start and End editors should display the date (and time) of the slot the user clicked on.
Last Updated: 20 Sep 2023 15:22 by ADMIN

Current behavior:

When I click on an empty slot in the Scheduler the Start and End DateTimePickers are set to the default value of a DateTime object - 1/1/0001. 

Expected/Desired behavior:

When I click on an empty slot in the Scheduler, the Start and End DateTimePickers should be set to the start and end date and time of the clicked slot.

Last Updated: 20 Sep 2023 11:15 by ADMIN
Scheduled for 4.7.0 (22 Nov 2023) (R1 PI1)


I'm trying to add image previewing to our .Net 6.0.8 Blazor Wasm app using the Telerik Blazor UI FileSelect component. I'd like to be able to create a local url for previewing and also hold onto the file's contents for saving later. There currently doesn't seem to be any great examples/references for doing this using the Telerik FileSelect locally. So, I started looking at the official MS Blazor documentation around images, file uploads and downloads - the most relevant content seemed to be around giving a file's stream to a DotNetStreamReference, then handing it off to JS interop to create a URL from a Blob.

It was already quite slow when testing with a 4KB~ image, but became absolutely unusable once testing things with a larger 4MB~ image. To rule out the Telerik FileSelect's involvement I started testing with the native Blazor FileInput component. I noticed that the sending the DotNetStreamReference to JS interop took a long time itself and learned that .Net 6 added the ability to pass a byte[] almost instantly to JS interop. I was then able to see image previews quickly using the native FileInput component while hosting a file from a byte[]. With this new knowledge in hand I attempted to migrate this new workflow over to the Blazor FileSelect component, but unfortunately there doesn't seem to be a faster way to get a byte[] from the FileSelectFileInfo's Stream.

I'm seeing similar performance issues between the native FileInput using a stream and the Telerik FileSelect using a stream or byte[]. These are both taking around 4-5 minutes to host a file with a locally generated url and preview the image. In contrast I'm seeing wait times around 3-12 seconds using the native FileInput/IBrowserFile, this

byte[] iBrowserFileBytes = new byte[iBrowserFile.Size];
await iBrowserFile.OpenReadStream(maxFileSize).ReadAsync(iBrowserFileBytes);

Please see the attached Blazor Wasm code to recreate the issue. I've included 6 file inputs to test out the difference in performance between each scenario, but the most important file input is the "Blazor InputFile - HostFromByteArray" which shows the most promise. Attached is also the larger file that I was testing against. This might be a bug or maybe I'm just not reading from the FileSelectFileInfo's Stream in the most efficient way.

The only relevant code not attached is likely just this one from Program.cs:

// ...
builder.Services.AddSingleton<IJSInProcessRuntime>(services => (IJSInProcessRuntime)services.GetRequiredService<IJSRuntime>());
// ...
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