Unplanned
Last Updated: 11 Jul 2025 07:41 by Rahul
The arguments within the OnDrop event are incorrectly calculated when a hierarchical grid row is expanded. This is likely because the expanded detail zone is being mistaken for a data row by the drag-and-drop algorithm.
Completed
Last Updated: 10 Jul 2025 13:35 by ADMIN
Release 2025 Q3 (Aug)

---

ADMIN EDIT

Screen recording attached below, code to reproduce  it too.

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Completed
Last Updated: 10 Jul 2025 13:35 by ADMIN
Release 2025 Q3 (Aug)
Created by: Rusli
Comments: 0
Category: ListBox
Type: Bug Report
2
The drag and drop functionality of the ListBox does not work on Android. When you try to drag an item, the item does not move.
Completed
Last Updated: 10 Jul 2025 13:35 by ADMIN
Release 2025 Q3 (Aug)
Created by: David
Comments: 0
Category: Scheduler
Type: Bug Report
1

The appointment drag and drop functionality of the Scheduler does not work on mobile devices. When you try to drag an item, the item does not move.

You can test it by running the Scheduler overview demo by using Chrome's mobile device emulator and trying to drag and drop an appointment.

Unplanned
Last Updated: 10 Jul 2025 09:39 by Patrik Madliak

Description

Entering/Removing spaces in between words does not trigger the ValueChanged event.

Steps To Reproduce

Run this example: https://blazorrepl.telerik.com/wzELPuOs30WSuvzv33

  1. Click between the "Lorem" and "ipsum" words.
  2. Press the Spacebar key a few times
  3. Press the Backspace key a few times

Actual Behavior

The ValueChanged event does not fire when you enter/remove spaces in between words. It fires correctly if you break a word with a space of if you remove all the spaces in between 2 words.

Expected Behavior

ValueChanged should fire on every entered/removed space.

Browser

All

Last working version of Telerik UI for Blazor (if regression)

No response

Completed
Last Updated: 09 Jul 2025 14:37 by Alexander
Release 2025 Q1 (Feb)

Pressing Shift+Tab initially when the Window is opened, moves the focus from the Window back to the Button that opens it.

Steps To Reproduce:

  1. Open REPL repro
  2. Click "Open Modal" Button
  3. Press "Shift+Tab"
Unplanned
Last Updated: 09 Jul 2025 12:39 by Paul
The keyboard navigation within the Editor’s toolbar does not behave as expected. For instance, when using custom tools, the Format dropdown cannot be navigated with the arrow keys: https://blazorrepl.telerik.com/QTOLEsFe05z7yxMY43
Declined
Last Updated: 09 Jul 2025 10:16 by ADMIN
Created by: Rob
Comments: 3
Category: Grid
Type: Bug Report
0

Grid OnRead .Clear() Issue

With the following component:

@page "/counter"
@using System.Collections.ObjectModel
General grid with its most common features
<TelerikGrid Data="@MyData" Pageable="true" @bind-Page="page" PageSize="5" TotalCount="30" OnRead="@ReadItems" >
    <GridColumns>
        <GridColumn Field="@(nameof(SampleData.Id))" Width="120px" />
        <GridColumn Field="@(nameof(SampleData.Name))" Title="Employee Name" Groupable="false" />
        <GridColumn Field="@(nameof(SampleData.Team))" Title="Team" />
        <GridColumn Field="@(nameof(SampleData.HireDate))" Title="Hire Date" />
    </GridColumns>
</TelerikGrid>

@code {
    public List<SampleData> MyData { get; set; } = new List<SampleData>();
    //public ObservableCollection<SampleData> MyData { get; set; } = new ObservableCollection<SampleData>();
    private int page = 1;

    private void ReadItems(GridReadEventArgs args)
    {
        //MyData = new List<SampleData>();  //OK!
        //MyData = new ObservableCollection<SampleData>(); //OK!
        MyData.Clear();  //List: No update. ObservableCollection: System.StackOverflowException!
        Populate();
        StateHasChanged();
    }

    private void Populate()
    {
        foreach (var data in Enumerable.Range((page - 1) * 5, 5).Select(x => new SampleData
        {
            Id = x,
            Name = "name " + x,
            Team = "team " + x % 5,
            HireDate = DateTime.Now.AddDays(-x).Date
        }))
        {
            MyData.Add(data);
        }
    }

    public class SampleData
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string Team { get; set; }
        public DateTime HireDate { get; set; }
    }
}

I see the issues in the comment fields.  Changing OnRead to async makes no difference.  

The workaround is to assign a new List or ObservableCollection instead of using .Clear()

Unplanned
Last Updated: 09 Jul 2025 08:24 by ADMIN
Created by: Sascha
Comments: 1
Category: UI for Blazor
Type: Bug Report
5

In our application we use some large datasets and present them in a TelerikGrid. We use WPF + Blazor Hybrid and noticed, that in some cases the memory usage of the Web View process grows up to some gigabytes.

Here a screenshot of the task manager with a lot of RAM usage for the web view.

Here a screenshot of the detached DOM elements after a two navigations. The container divs are not garbage collected.

I tracked down the issue to come from the TelerikGrid, because when I remove it from the pages, everything runs fine. I also removed all GridColumns and the issue is still present. In the developer tools I noticed that one of the parent div elements remains in memory every time I navigate back and forth.

I also created a blank Blazor WebAssembly Standalone application and added a simple instance of the grid. Here, the issue is also present. I attach the one blazor page that causes the issue.

I've tested all major versions from 5.1 upwards, every version is affected.

Duplicated
Last Updated: 09 Jul 2025 08:24 by ADMIN
Created by: Alexander
Comments: 0
Category: Grid
Type: Bug Report
2

Refreshing the Grid data frequently may cause performance issues.

Completed
Last Updated: 08 Jul 2025 05:51 by ADMIN
Release 2025 Q3 (Aug)
Created by: Juni
Comments: 0
Category: PDFViewer
Type: Bug Report
3
When printing a PDF using the `TelerikPdfViewer` via the built-in Print tool or programmatically through the `Print()` method, the output is scaled down to approximately 75% of its original size.
Completed
Last Updated: 07 Jul 2025 12:51 by ADMIN
Release 2025 Q3 (Aug)

I'm using the Menu component and I am handling the OnClick event. I noticed that when an exception is thrown in its handler, it does not reach the ErrorBoundary.

===

ADMIN EDIT

===

This issue also affects the SplitButton component.

Unplanned
Last Updated: 07 Jul 2025 08:11 by Alexander
Created by: Alexander
Comments: 0
Category: Grid
Type: Bug Report
1

The focus indicator on the GridSearchBox is broken when using an outline themes like A11Y, Bootstrap etc.

Workaround:

Temporarily override the overflow style on .k-toolbar-items (e.g., overflow: unset;) using custom CSS to restore the focus indicator.

Completed
Last Updated: 03 Jul 2025 12:47 by ADMIN
Release 2025 Q3 (Aug)

The input in the DateTimePicker is valid when:

- the DateTimePicker value is bound to nullable DateTime and

- the user clears the input

In such cases, the input field shouldn't get a red border.

Here is a REPL example to reproduce the issue:

  1. Select a date.
  2. Clear the date. The input gets a red border.

===ADMIN EDIT===

A possible workaround is to change the border color with CSS. Here is a REPL example.


Completed
Last Updated: 03 Jul 2025 11:13 by ADMIN

I've noticed this warning is now shown since version 9.0.0. I checked the release notes and don't see any notes reflecting this change. I also checked the documentation and don't see any information about the OnUpdate event. Can we please update the documentation to document the changes? I would like to understand the behavior of OnUpdate so I can move away from ValueChanged.

"warning CS0618: 'TelerikFilter.ValueChanged' is obsolete: 'Use OnUpdate instead.'"

Blazor Filter Events - Telerik UI for Blazor

Completed
Last Updated: 01 Jul 2025 13:35 by ADMIN
Release 2025 Q2 (May)

Hello,

I created a repl to replicate the issue that I'm having. I created a Filter with a custom editor. For this example, I used a Textbox and I save the changes back to the context.FilterDescriptor.Value in the OnChange method which occurs when the user blurs focus.

If you start the repl w/o checking the Use Custom Editor checkbox and enter text where the "Sample" value is located you will see the changes are saved properly to the bound CompositeFilter property and are echo'd back in the screen.

If instead you check the Use Custom Editor box and perform the same test you'll see that the same changes are not present in the bound CompositeFilter. 

Note that this issue only occurs if you start with an existing CompositeFilter and bind it to the filter control. It seems that if the control creates the FilterDescriptor objects then their changes bind properly, but if the FilterDescriptor objects existed before binding to the control then the issue occurs.

https://blazorrepl.telerik.com/wIOtcKOb31mjTc3351

Thank You,

-Andy

============= TELERIK EDIT ===============

A possible workaround is to find the original filter descriptor and update its Value:

@using Telerik.DataSource

@System.Text.Json.JsonSerializer.Serialize(FilterValue)

<br />
<br />

<TelerikFilter @bind-Value="@FilterValue">
    <FilterFields>
        <FilterField Name="Field" Type="@(typeof(string))">
            <ValueTemplate>
                <TelerikTextBox Value="@((string)context.FilterDescriptor.Value)"
                                ValueChanged="@( (string newValue) => OnTextBoxValueChanged(context.FilterDescriptor, newValue) )"
                                DebounceDelay="0" />
            </ValueTemplate>
        </FilterField>
    </FilterFields>
</TelerikFilter>

@code {
    private void OnTextBoxValueChanged(FilterDescriptor templateFD, string newValue)
    {
        var originalFD = FilterValue.FilterDescriptors.OfType<FilterDescriptor>().FirstOrDefault(x =>
        {
            return x.Member == templateFD.Member &&
                x.MemberType == templateFD.MemberType &&
                x.Operator == templateFD.Operator &&
                x.Value == templateFD.Value;
        });

        if (originalFD != null)
        {
            templateFD.Value = newValue;
            originalFD.Value = newValue;
        }
    }

    private CompositeFilterDescriptor FilterValue { get; set; } = new()
    {
        LogicalOperator = FilterCompositionLogicalOperator.Or,
        FilterDescriptors = new FilterDescriptorCollection() {
             new FilterDescriptor()
            {
                Member = "Field",
                MemberType = typeof(string),
                Value = "Sample"
            }
         }
    };
}

 

Unplanned
Last Updated: 01 Jul 2025 12:33 by Julia
The AriaLabel parameter should render the aria-label attribute on the ul element as per the latest accessibility standards.
Unplanned
Last Updated: 30 Jun 2025 10:59 by ADMIN

The following date in the Scheduler RecurrenceRule cannot be parsed and is ignored:

RecurrenceRule = "FREQ=DAILY;UNTIL=20210722T000000"

According to the RFC5545 specification, this should be a valid date format.

These formats will work:

RecurrenceRule = "FREQ=DAILY;UNTIL=2021-07-22T00:00:00"
RecurrenceRule = "FREQ=DAILY;UNTIL=2021-07-22T00:00:00.000Z"

 

EDIT:

This is my work-around. It captures the date portion of the UNTIL clause, converts it into the date string style that Telerik can understand, then reassembles the rule string

private string TransformRecurrenceRule()
        {
            const string untilSeparator = "UNTIL=";
            var ruleParts = RecurrenceRule.Split(untilSeparator, StringSplitOptions.RemoveEmptyEntries);
            if (ruleParts.Length <= 1)
            {
                // There was no Until clause to worry about
                return RecurrenceRule;
            }

            // Save the first part of the rule
            var ruleBeginning = ruleParts[0];

            // Split the date part of the until clause from any following clauses
            var remainingClauses = ruleParts[1].Split(';', 2, StringSplitOptions.RemoveEmptyEntries);

            //Save the date part of the until clause
            var untilDate = remainingClauses[0];

            // Save any following clauses with the `;` replaced
            var ruleEnding = "";
            if (remainingClauses.Length == 2)
            {
                ruleEnding = $";{remainingClauses[1]}";

            }

            // Convert the until date into .net parsable format
            const string format = "yyyyMMddTHHmmss";
            var date = DateTime.ParseExact(untilDate, format, CultureInfo.InvariantCulture);
            var dateStr = date.ToString("yyyy-MM-ddTHH:mm:ss");

            // recombine rule components
            var newRuleParts = new[] {ruleBeginning, untilSeparator, dateStr, ruleEnding};
            var newRule = string.Join("",newRuleParts);

            return newRule;
        }

Unplanned
Last Updated: 30 Jun 2025 10:01 by David

The NumericTextBox does not render the new Value that is set in ValueChanged if this new value is different than the event argument. Instead, the component clears the textbox, even though the component Value parameter is correct.

https://blazorrepl.telerik.com/wzaAHYas221go9xd48

The problem occurs only if there is an existing value and the user removes it with Backspace.

Completed
Last Updated: 27 Jun 2025 14:12 by ADMIN
Release 2025 Q3 (Aug)
When you right-click an item to open the Context Menu and select the "Delete" option, the confirmation dialog appears hidden behind the menu.
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