Unplanned
Last Updated: 23 Aug 2026 17:24 by ADMIN
Scheduled for 2026 Q4 (Nov)
Created by: Sam
Comments: 0
Category: DropDownList
Type: Bug Report
0

Bug report

Reproduction of the problem

(bug report only)
The DropDownList (and other dropdown components - ComboBox, MultiColumnComboBox, etc.) render a redundant attribute in their popup ul element: aria-live="polite". Listboxes that use aria-activedescendant for tracking should not also announce via a live region — this creates duplicate/conflicting announcements by screen readers.

Current behavior

(optional)
The popup’s ul element renders aria-live=”polite”.

Expected/desired behavior

Either render aria-live=”off” (e.g., Kendo Angular DropDownList), or don’t render the aria-live attribute at all.

Environment

  • Kendo/Telerik version:
  • jQuery version: x.y
  • Browser: [all]
Completed
Last Updated: 21 Aug 2026 13:21 by ADMIN
Release 2026 Q4 (Nov)

Bug report

Reproduction of the problem

(bug report only)
Regression introduced in 13.0.0.
1. Run this example: https://blazorrepl.telerik.com/wUuSGClv00orFeRm59

Current behavior

(optional)
The Size, Rounded, FillMode parameters are ignored.

Expected/desired behavior

The parameter values should apply and change the appearance of the SearchBox.

Environment

  • Browser: [all ]
In Development
Last Updated: 21 Aug 2026 08:34 by ADMIN
Scheduled for 2026 15.1.0 (Sep)
Created by: laboratorysystemdevelopment
Comments: 0
Category: ComboBox
Type: Bug Report
1

The ComboBox and MultiColumnComboBox retain their TextField string label when the value is cleared programmatically. The issue starts to occur in version 14.1.0.

Test Page:

<ul>
    <li><code>AutoCompleteValue</code>: @AutoCompleteValue</li>
    <li><code>SelectedValue</code>: @SelectedValue</li>
    <li><code>SelectedValueNullable</code>: @SelectedValueNullable</li>
    <li><code>MultiSelectValues</code>: @string.Join(", ", MultiSelectValues)</li>
</ul>

<p>
    <TelerikButton OnClick="@(() => {
        AutoCompleteValue = string.Empty;
        SelectedValue = default;
        SelectedValueNullable = default;
        MultiSelectValues = new();
    })">Clear Values</TelerikButton>
</p>

<TelerikAutoComplete Data="@ListItems"
                     @bind-Value="@AutoCompleteValue"
                     ValueField="@nameof(ListItem.Text)"
                     Placeholder="Select Item"
                     ShowClearButton="true"
                     Width="300px" />

<br /><br />

<TelerikComboBox Data="@ListItems"
                 @bind-Value="@SelectedValue"
                 TextField="@nameof(ListItem.Text)"
                 ValueField="@nameof(ListItem.Id)"
                 Placeholder="Select Item"
                 ShowClearButton="true"
                 Width="300px" />

<TelerikComboBox Data="@ListItems"
                 @bind-Value="@SelectedValueNullable"
                 TextField="@nameof(ListItem.Text)"
                 ValueField="@nameof(ListItem.Id)"
                 Placeholder="Select Item"
                 ShowClearButton="true"
                 Width="300px" />


<br /><br />

<TelerikDropDownList Data="@ListItems"
                     @bind-Value="@SelectedValue"
                     TextField="@nameof(ListItem.Text)"
                     ValueField="@nameof(ListItem.Id)"
                     DefaultText="Select Item"
                     Width="300px" />

<TelerikDropDownList Data="@ListItems"
                     @bind-Value="@SelectedValueNullable"
                     TextField="@nameof(ListItem.Text)"
                     ValueField="@nameof(ListItem.Id)"
                     DefaultText="Select Item"
                     Width="300px" />

<br /><br />

<TelerikMultiColumnComboBox Data="@ListItems"
                            @bind-Value="@SelectedValue"
                            TextField="@nameof(ListItem.Text)"
                            ValueField="@nameof(ListItem.Id)"
                            Placeholder="Select Item"
                            ShowClearButton="true"
                            Width="300px">
    <MultiColumnComboBoxColumns>
        <MultiColumnComboBoxColumn Field="@nameof(ListItem.Id)" />
        <MultiColumnComboBoxColumn Field="@nameof(ListItem.Text)" />
    </MultiColumnComboBoxColumns>
</TelerikMultiColumnComboBox>

<TelerikMultiColumnComboBox Data="@ListItems"
                            @bind-Value="@SelectedValueNullable"
                            TextField="@nameof(ListItem.Text)"
                            ValueField="@nameof(ListItem.Id)"
                            Placeholder="Select Item"
                            ShowClearButton="true"
                            Width="300px">
    <MultiColumnComboBoxColumns>
        <MultiColumnComboBoxColumn Field="@nameof(ListItem.Id)" />
        <MultiColumnComboBoxColumn Field="@nameof(ListItem.Text)" />
    </MultiColumnComboBoxColumns>
</TelerikMultiColumnComboBox>

<br /><br />

<TelerikMultiSelect Data="@ListItems"
                    @bind-Value="@MultiSelectValues"
                    TextField="@nameof(ListItem.Text)"
                    ValueField="@nameof(ListItem.Id)"
                    Placeholder="Select Items"
                    ShowArrowButton="true"
                    ShowClearButton="true"
                    AutoClose="false"
                    Width="600px" />

@code {
    private List<ListItem> ListItems { get; set; } = new();

    private int SelectedValue { get; set; } = 3;
    private int? SelectedValueNullable { get; set; } = 3;
    private string AutoCompleteValue { get; set; } = "Item 3";

    private List<int> MultiSelectValues { get; set; } = new() { 3, 5 };

    protected override void OnInitialized()
    {
        ListItems = new List<ListItem>();

        for (int i = 1; i <= 24; i++)
        {
            ListItems.Add(new ListItem()
            {
                Id = i,
                Text = $"Item {i}"
            });
        }

        base.OnInitialized();
    }

    public class ListItem
    {
        public int Id { get; set; }
        public string Text { get; set; } = string.Empty;
    }
}

Planned
Last Updated: 20 Aug 2026 10:28 by ADMIN
Scheduled for 2026 Q4 (Nov)
Created by: Indra
Comments: 2
Category: DropDownList
Type: Bug Report
8

I have a cascading DropDownList scenario with virtual scrolling. When the first DropDownList changes value, the second one should reset its scrollbar to the top, because it now contains new data. This doesn't happen.

Here is a REPL test page.

===

ADMIN EDIT

===

As a workaround for the time being, you may track when the value is changed in the parent DropDownList to dispose and re-initialize the child DropDownList.

Here is an example: https://blazorrepl.telerik.com/mdafHabk585ZtzyV54.

Planned
Last Updated: 20 Aug 2026 10:12 by ADMIN
Scheduled for 2026 Q4 (Nov)
Created by: Sebastian
Comments: 2
Category: PDFViewer
Type: Bug Report
1
  • The PDF Viewer does not display the initial file if Zoom is set to FitToWidth or FitToPage. This is due to --scale-factor: NaN; --total-scale-factor: NaN; set on the PDF Viewer element.
  • If the PDF Viewer initially shows with no loaded file, setting Zoom to FitToWidth or FitToPage initially or after opening a file leads to infinity zoom due to --scale-factor: Infinity; --total-scale-factor: Infinity; set on the PDF Viewer element.

The only scenario that works is to set the initial Zoom to a numeric value and have an open file by default.

Planned
Last Updated: 20 Aug 2026 10:11 by ADMIN
Scheduled for 2026 Q4 (Nov)

I am trying to look at the times 7pm - midnight.  But if I set the end time to midnight, I get an error that the end time has to be greater than the start time.  How do I set the timeline to show 7pm - midnight or 8pm - 2am?

I tried including the next date in the EndTime but the Scheduler does not take the date into consideration, it checks only the time portion.

Completed
Last Updated: 20 Aug 2026 10:10 by ADMIN
Release 2026 14.1.0 (Jul)

I am resetting the Grid State by calling Grid.SetState(null). This doesn't reset ColumnState<T>.Locked boolean to false and the columns remain locked.

---

ADMIN EDIT

---

A possible workaround for the time being is to additionally loop through the ColumnStates collection of the State and set the Locked property to false for each column.

Example: https://blazorrepl.telerik.com/QTYmkpvb49c6CPxa42

Completed
Last Updated: 20 Aug 2026 09:43 by ADMIN
Release 2026 14.1.0 (Jul)

When Adaptive = true, changing the collection of buttons seems to "break" the adaptive calculation. The Toolbar fails to determine what are the buttons to show in the main element and what are the buttons to show in the pop-up: https://blazorrepl.telerik.com/wSubOWlS08FLz7aZ54

===

ADMIN EDIT

For the time being, a possible workaround is to force the component to refresh when you change the buttons. For that purpose, you can dispose it and re-initialize it after some delay. Here is a runnable sample: https://blazorrepl.telerik.com/QIOFuCvS400o5tfL34.

In Development
Last Updated: 19 Aug 2026 14:33 by Andreas
Created by: Andreas
Comments: 2
Category: UI for Blazor
Type: Bug Report
2

We have a Blazor project that normally takes 20 seconds to build.

But after upgrading Telerik.Licensing from 1.8.2 to 1.9.0/1 the build takes about 60 seconds.

First we upgraded all telerik references with this effect. Now we downgraded all to the version that is supported by 1.8.2.

In the project, the only change I make is to change the version from 1.8.2 to 1.9.0 or later, then the build goes from 20 seconds to 60 seconds, no other changes made...

I have tried Rebuild, Restarts etc...

In the build detailed output, it is the csc command that takes longer times.

Unplanned
Last Updated: 19 Aug 2026 14:05 by Oriol

Bug report

Reproduction of the problem

(bug report only)
Run this example: https://blazorrepl.telerik.com/GqaiPtbH54zmCKSH29
There are two editable columns (Price).
1. Click on the first Price column cell in the first row.
2. Press Tab key. The last editable cell on the first row is focused and is brought into view.
3. Press Tab again. The first editable cell on the second row is focused and brought into view.
4. Press Tab again. The last editable cell on the second row is focused, but it is not brought into view.

Current behavior

(optional)

Navigation across editable cells works inconsistently. On every other row, the last editable cell is not brought into view.

Expected/desired behavior

Navigation should work consistently on every row.

Environment

  • Kendo/Telerik version: 15.0.0
  • jQuery version: x.y
  • Browser: [all]
Completed
Last Updated: 18 Aug 2026 14:33 by ADMIN
Release 2026 14.1.0 (Jul)

I've determined that the TelerikDateTimePicker does not work properly on mobile devices when using AdaptiveMode.Auto. Attached are videos of the component's behaviour in both modes (None, and Auto).

Immediately after interacting with the fullscreen popup of the datepicker, I see this error in the console:

RAW:
telerik-blazor.js:50 Uncaught TypeError: r.isParent is not a function

    at p.isChild (telerik-blazor.js:50:1362352)
    at f.closePopup (telerik-blazor.js:50:1398427)
    at HTMLHtmlElement.onMouseDown (telerik-blazor.js:50:1397246)

Code:

@using Telerik.Blazor.Components
@using Telerik.Blazor

<TelerikFloatingLabel Text="Date & Time">
    <TelerikDateTimePicker Id="date-picker" @bind-Value="MyFormModel.Date" Max="@DateTime.Now.AddDays(1)"
                           Format="@DATE_FORMAT" AdaptiveMode="AdaptiveMode.Auto"
                           FillMode="@Telerik.Blazor.ThemeConstants.DateTimePicker.FillMode.Flat" />
</TelerikFloatingLabel>
@code {
    private FormModel MyFormModel { get; set; } = new FormModel();
    private const string DATE_FORMAT = "MM/dd/yyyy HH:mm";

    private class FormModel
    {
        public DateTime Date { get; set; }
    }
}

Notes:
- If we remove all of the parent components wrapping the DatePicker, it seems to function properly, but the errors remain in the console. This isn't a solution, however.

Declined
Last Updated: 18 Aug 2026 14:00 by ADMIN
Scheduled for 2026 Q3 (Aug)

We have a grid with a GridCheckboxColumn that we have configured through a '.unselectable-row' style so that certain elements cannot be selected (those elements with a padlock in the second column cannot be selected).

The grid works correctly in isolation, but when we add a TelerikLoaderContainer that is displayed during data loading process, the grid doesn't working properly: it is possible to select all the enabled elements of the grid using the button in the header of the checkbox column. However it is not possible to deselect them from the button in the header of the checkbox column when there is any unselectable element.

Here it is a link to REPL with a reproducible example: https://blazorrepl.telerik.com/GyYhYXPI24gIYgIJ03

To reproduce the problem, you sholud select all grid elements from the checkbox column header button and try to deselect them. You will not be able to deselect all the elements. 
Now comment the LoaderContainer component and repeat the test. You will see that now it is possible to deselect correctly all the elements.

How can we deselect all the elements from the header while keeping the loadercontainer?

Completed
Last Updated: 18 Aug 2026 13:21 by ADMIN
Release 2026 Q2

I am using ComboBox and I want to be able to filter by two model properties. To achieve this I have implemented custom filtering through the OnRead event. Additionally, I am ordering the data to first match the results from the one property, which also is used for the TextField, and after that to match the results from the other property. However, when the results are only from the match of the second property, there is no focus.

Here is a REPL example https://blazorrepl.telerik.com/wyaMQhEN108axXJ036 

Steps to reproduce the issue:

Type "a": "Value test - ano" has the focus (the first option in the list)

Type "an": "Value test - ano" receives the focus (the first option in the list)

Type "ano": "Value test - ano" receives the focus (the first option in the list)

Type "anot": no item has focus despite the results being only "Another Value - val"

Completed
Last Updated: 18 Aug 2026 11:37 by ADMIN
Release 2026 Q2
Enter "01" in the "hour" section. You’ll notice that the cursor does not automatically move to the next section until another digit is entered.
Completed
Last Updated: 18 Aug 2026 11:34 by ADMIN
Release 2026 Q2

When SchedulerGroupOrientation is set to vertical, increasing the height of the `SchedulerResourceGroupHeader` breaks the rendering of the Scheduler cells, which causes misalignment of the appointments. In my scenario, I want to have a Button and an Icon in the group header cell.

Reproduction example: https://blazorrepl.telerik.com/wJElGYvF02XSsN6j42

Completed
Last Updated: 18 Aug 2026 10:57 by ADMIN
Release 2026 Q1 (Feb)

This is a continuation of public item DatePicker, TimePicker and DateTimePicker should accept null value as valid when bound to nullable DateTime

The problem persist when:

  • The component Format includes a week day.
  • The component Format is set with a standard date format string (d, D, g, etc.)

Test page with workarounds:

Bug due to week day format string inconsistency between .NET and JavaScript (dddd vs EEEE):

<TelerikDateTimePicker @bind-Value="@SelectedTime"
                       ShowClearButton="true"
                       Width="360px">
    <DateTimePickerFormatPlaceholder Weekday="week" />
</TelerikDateTimePicker>

<br />
<br />

Bug due to usage of a standard date format string:

<TelerikDatePicker @bind-Value="@SelectedTime"
                   ShowClearButton="true"
                   Format="d"
                   Width="360px">
    <DateTimePickerFormatPlaceholder Day="dd" Month="mm" Year="yyyy" />
</TelerikDatePicker>

@code {
    private DateTime? SelectedTime = DateTime.Now;
}

 

Completed
Last Updated: 13 Aug 2026 12:51 by ADMIN
Release 2026 Q3 (Aug)
Focus is lost after selecting an item from the dropdown in Firefox, but only when using the mouse. When selecting an item via the keyboard, the focus remains on the input element as expected.
Completed
Last Updated: 13 Aug 2026 12:42 by ADMIN
Release 2026 14.1.0 (Jul)

We upgraded to the latest Telerik Blazor components (8.1.1).
I think there's a bug in the TabStrip when setting the index of the ActiveTabIndex or @bind-ActiveTabIndex.
The page will scroll to the active tab automatically.

Here's a link to the Repl - https://blazorrepl.telerik.com/GfaTEmbR45zQSzEq44

If you remove @bind-ActiveTabIndex="@ActiveTabIndex" from the TelerikTabStrip then the page load normally.

Thanks,

Cesar

Planned
Last Updated: 13 Aug 2026 12:34 by ADMIN
Scheduled for 2026 Q4 (Nov)

The NOW button in the TimePicker's TimeView sets the time value, according to the server's time zone. Instead, it should use the client-side (user) time zone.

===

Telerik edit:

In the meantime, you can subscribe to the TimePicker's ValueChanged event and detect when the user clicks on Now. In such cases, the event handler will receive the current server time with a small margin of error, that depends on the latency.

<TelerikTimePicker Value="@TimePickerValue"
                   ValueChanged="@( (DateTime? d) => TimePickerValueChanged(d) )">
</TelerikTimePicker>

@code {
    private DateTime? TimePickerValue { get; set; }

    private void TimePickerValueChanged(DateTime? newValue)
    {
        if (newValue.HasValue && newValue - DateTime.Now < new TimeSpan(0, 0, 1))
        {
            // Retrieve and set the correct user's local time. The dummy code below is just for testing.
            TimePickerValue = DateTime.Now.AddMinutes(2);
        }
        else
        {
            TimePickerValue = newValue;
        }
    }
}

Planned
Last Updated: 13 Aug 2026 12:33 by ADMIN
Scheduled for 2026 Q4 (Nov)

Bug report

Reproduction of the problem

(bug report only)
1. Run this example: https://blazorrepl.telerik.com/cUaBGOOZ34pkp6wB57
2. Inspect the MultiSelect’s input.
3. Click within the component’s input area, to open its popup.

The issue is also reproducible in the other dropdown components: https://blazorrepl.telerik.com/GUurGmvw32oPqGYu03

Current behavior

(optional)
When the dropdown opens, an aria-controls attribute is applied to the MultiSelect’s input. Its value does not match any existing DOM element.

Expected/desired behavior

The value of the aria-controls attribute should point at an existing element (e.g., the popup’s list element: https://www.telerik.com/blazor-ui/documentation/components/multiselect/accessibility/wai-aria-support#multiselect-wrapping-element ). But in this case the MultiSelect is not bound to data and a list element is not rendered in the popup.

Environment

  • Kendo/Telerik version: 14.1.0
  • jQuery version:
  • Browser: [all ]
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