Bug report

Reproduction of the problem

1. Set a culture in the app, e.g.,

Program.cs

CultureInfo.DefaultThreadCurrentCulture = new CultureInfo("fr-CA");
CultureInfo.DefaultThreadCurrentUICulture = new CultureInfo("fr-CA");

2. Add a basic Scheduler with Agenda view enabled.

Current behavior

The weekdays in the Agenda view date headers are not translated in the language set by the culture.

Expected/desired behavior

The weekdays in the Agenda view are translated. Note that they are properly translated in other views, e.g., Week and Month.

Environment

• Kendo/Telerik version: 13.1.0
• Browser: [all ]

When ActiveTabId is null, the TabStrip selects the first tab automatically, but does not render its content.

<TelerikTabStrip @bind-ActiveTabId="@TabStripActiveTabId">
    <TabStripTab Title="First" Id="t1">
        First tab content.
    </TabStripTab>
    <TabStripTab Title="Second" Id="t2">
        Second tab content.
    </TabStripTab>
    <TabStripTab Title="Third" Id="t3">
        Third tab content.
    </TabStripTab>
</TelerikTabStrip>

@code {
    private string? TabStripActiveTabId { get; set; }
}

Goal

Our application needs to allow end users to dynamically customize the Telerik Blazor DockManager at runtime by:

• Adding new panels
• Removing existing panels
• Rearranging and resizing panels

These changes should be fully user-driven and persisted so that:

• The layout is restored when the user returns
• The layout is consistent across browsers and devices

In short, we want the DockManager to behave as a customizable dashboard whose state can be reliably stored and reloaded from our database.

Problem

The current Telerik Blazor DockManager implementation requires panels to be declared in Razor markup (markup driven) and managed through an external data source.

This creates several challenges:

• The component state (DockState) is tightly coupled to the initial panel definitions.
• Dynamically adding or removing panels from the data source conflicts with the internal DockState.
• To synchronize changes, we must manually manipulate the DockState object using custom code.
• This manipulation relies on internal behavior that is not formally supported and may break in future Telerik releases.

As a result, implementing a truly dynamic and persistent DockManager layout requires complex workarounds that are fragile and difficult to maintain.

Feature Request

We propose enhancing the DockManager with first-class support for dynamic panel synchronization by introducing:

Two coordinated parameters:

• Data – the collection of panels
• DockState – the persisted layout information

Expected behavior:

• If the Data collection contains a panel that is not present in the DockState, the component should automatically:
  • Add the new panel to the layout
  • Place it at the end of the current structure (bottom or right, depending on layout)
  • Update the DockState accordingly
• If the DockState contains a panel that is no longer present in the Data collection, the component should automatically:
  • Remove that panel from the layout
  • Update the DockState accordingly

This would allow developers to treat the DockManager as a true data-driven component, similar to other Telerik Blazor controls, without needing to manually modify internal state structures.

Title: WCAG 1.3.1: Ensures elements with an ARIA role that require child roles contain them (#\39 374a450-079d-4586-b823-d6bc7723505f)
Tags: Accessibility, WCAG 1.3.1, aria-required-children

Issue: Ensures elements with an ARIA role that require child roles contain them (aria-required-children - https://accessibilityinsights.io/info-examples/web/aria-required-children)

Target application: Hermes Home - https://localhost/TrafficLoss

Element path: #\39 374a450-079d-4586-b823-d6bc7723505f

Snippet: <div class="k-grid-aria-root" id="9374a450-079d-4586-b823-d6bc7723505f" role="grid" aria-label="Data table">

How to fix: 
Fix any of the following:
  Element has children which are not allowed (see related nodes)
  Element has no aria-busy="true" attribute

Environment: Microsoft Edge version 111.0.1661.41

====

This accessibility issue was found using Accessibility Insights for Web 2.37.3 (axe-core 4.6.3), a tool that helps find and fix accessibility issues. Get more information & download this tool at http://aka.ms/AccessibilityInsights.

============================  code =============================

                           <TelerikGrid Data="@ViewModel.RDLInformation" TItem="TLSummary"
                                                        Pageable="true" 
                                                        Sortable="true" 
                                                        Groupable="false"
                                                        FilterMode="Telerik.Blazor.GridFilterMode.FilterRow"
                                                        Resizable="true" 
                                                        Reorderable="true"
                                                        Height = "100%">

....

                            </TelerikGrid>

Currently, on mobile devices (where is no hover), to open the child menu you need to click/tap the parent and the only way close it afterwards is if you click away. This is not very convenient for mobile usage. I want to be able to close the child menu on click/tap of the parent as well.

The ability to choose which options to appear in the ContextMenu.

=====

TELERIK EDIT: In the meantime, here is how to hide context menu items with CSS:

    /* Hide the Rename item in the FileManager context menu */
    .k-context-menu:has(.k-svg-i-download) .k-menu-item:nth-of-type(1) {
        display: none;
    }

    /* Hide the Delete item in the FileManager context menu */
    .k-context-menu:has(.k-svg-i-download) .k-menu-item:nth-of-type(3) {
        display: none;
    }

Here is a complete example: https://blazorrepl.telerik.com/cpPkuBEq408A36p010

Description

When the dropdown is open, the button's aria-controls attribute references a value that matches the popup's data-id, not its actual id. Since aria-controls must point to an element's id, the attribute is invalid and no element in the DOM matches the reference, breaking the accessible relationship between the button and its popup. 

Button renders:

aria-controls="50dc5df2-b83e-41bd-8c34-98470aba77c6"

Popup element has:

data-id="50dc5df2-b83e-41bd-8c34-98470aba77c6"
id="8630d4e4-2f22-4eaf-b96c-7cae113b70ed"

Steps to Reproduce

1. Add a TelerikDropDownButton using the standard Telerik example (source below).
2. Open the dropdown and inspect the HTML or run a Lighthouse audit.

<TelerikDropDownButton Icon="@SvgIcon.Share" OnClick="@(()=>OnItemClick("Primary"))">
    <DropDownButtonContent>Share</DropDownButtonContent>
    <DropDownButtonItems>
        <DropDownButtonItem Icon="@SvgIcon.Facebook" OnClick="@(()=>OnItemClick("Facebook"))">Facebook</DropDownButtonItem>
        <DropDownButtonItem Icon="@SvgIcon.Twitter" OnClick="@(()=>OnItemClick("Twitter"))">Twitter</DropDownButtonItem>
        <DropDownButtonItem Icon="@SvgIcon.Linkedin" OnClick="@(()=>OnItemClick("Linkedin"))">Linkedin</DropDownButtonItem>
        <DropDownButtonItem Icon="@SvgIcon.Reddit" OnClick="@(()=>OnItemClick("Reddit"))">Reddit</DropDownButtonItem>
    </DropDownButtonItems>
</TelerikDropDownButton>

If the ComboBox Value is set during initialization and the ValueMapper executes too fast and before the component has rendered, its Value doesn't show.

The problem also occurs in the MultiColumnComboBox.

Possible workarounds:

• Set the component Value a bit later.
• Delay the ValueMapper execution until OnAfterRenderAsync fires.
• Rebind() the ComboBox in OnAfterRenderAsync. This will fire OnRead again.
• Render the ComboBox conditionally in the first OnAfterRenderAsync call.

To reproduce:

@using Telerik.DataSource
@using Telerik.DataSource.Extensions

<p>ComboBox Value: @ComboBoxValue</p>

<TelerikComboBox ItemHeight="30"
                 OnRead="@OnComboBoxRead"
                 PageSize="20"
                 ScrollMode="@DropDownScrollMode.Virtual"
                 TItem="@ListItem"
                 TValue="@(int?)"
                 @bind-Value="@ComboBoxValue"
                 ValueMapper="@ComboBoxValueMapper"
                 Width="240px" />

@code {
    private List<ListItem>? ComboBoxData { get; set; }

    private int? ComboBoxValue { get; set; } = 3;

    private async Task OnComboBoxRead(ReadEventArgs args)
    {
        DataSourceResult result = await ComboBoxData.ToDataSourceResultAsync(args.Request);

        args.Data = result.Data;
        args.Total = result.Total;
    }

    private async Task<ListItem?> ComboBoxValueMapper(int? selectValue)
    {
        // Triggers the bug
        await Task.Yield();

        ListItem? result = ComboBoxData?.FirstOrDefault(x => selectValue == x.Value);

        return result;
    }

    protected override void OnInitialized()
    {
        ComboBoxData = Enumerable
            .Range(1, 1234)
            .Select(x => new ListItem()
                {
                    Value = x,
                    Text = $"Item {x}"
                })
            .ToList();
    }

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

Bug report

Reproduction of the problem

Possibly related to https://github.com/telerik/blazor/issues/2594

1. Run this example: https://blazorrepl.telerik.com/wAkdbZPo47oCuV5G32
2. Without scrolling the Grid horizontally resize a non-locked column (e.g., In Stock)

Current behavior

(optional)

The first locked column (ID) is rendered after the second locked column (Product Name). When you resize a non-locked column, the ID column disappears and is revealed at its new position after you scroll the Grid horizontally.
The behavior is reproducible with RTL enabled.

Expected/desired behavior

The order of the locked columns should persist.

Environment

• Telerik version: 13.0.0
• Browser: [all]

If LoadGroupsOnDemand="false", I am able to programmatically expand the groups through the state. However, this is not possible when loading group data on demand.

Please allow programmatically expanding the groups when LoadGroupsOnDemand="true". This should go together with an event (OnStateChanged?) that will fire when LOD groups are expanded or collapsed.

Draft feature request (copy/paste)

Title: Add per-column value converters (WPF-style) to Telerik Blazor Grid columns

Product: UI for Blazor → Grid
Type: Feature Request

Description:
In Telerik UI for WPF, grid column definitions can reference a converter by name (e.g., IValueConverter) to transform values for display without writing a custom cell template for each column.

In Telerik UI for Blazor Grid, templates are currently the primary way to change how values render in a column (which works, but becomes repetitive across many columns/grids).

Request:
Add a column-level conversion API that allows specifying a converter/formatter function for display (and optionally editing). Example concepts:

• Converter="nameof(MyConverters.StatusToText)"

• or DisplayConverter="(item) => …" / ValueFormatter="Func<TItem, object, string>"

• optionally ConvertBack-like support for editing scenarios (or separate EditConverter)

Why this is needed:

• Reduces repeated <Template> markup for simple formatting/transformations

• Centralizes formatting/conversion logic in reusable code

• Improves maintainability and consistency across grids

• Eases migration for teams coming from Telerik WPF where converters are a common pattern

Use cases:

• Enum/int → user-friendly text

• Boolean → “Yes/No”, icons, badges

• Null/empty → placeholder text

• Code → display name (via lookup)

• Domain-specific formatting shared across many grids

Workarounds today:

• Column <Template> or computed properties (both valid, but not as concise/reusable for large grids)

• Extracting RenderFragments can reduce repetition, but still requires templating infrastructure for what is logically a simple conversion step

Expected behavior:

• Converter applies consistently anywhere the column renders (cell, export if applicable, etc.)

• Works with sorting/filtering in a predictable way (ideally sorting/filtering still uses raw field value unless explicitly configured)

Description

When the dropdown is open, the input's aria-activedescendant attribute references an id that does not exist in the DOM. Since aria-activedescendant must point to the id of an actually rendered option element, the attribute is invalid and assistive technologies cannot determine which option is currently active.

Input renders:

aria-activedescendant="b45bcb14-4093-4de8-ad31-cae8ec8ca9c4"

Steps to Reproduce

1. Add a TelerikMultiSelect using the standard Telerik example (source below).
2. Open the dropdown and inspect the HTML or run a Lighthouse audit.

<TelerikMultiSelect Data="@Hobbies"
@bind-Value="@SelectedHobbyIds"
ValueField="@nameof(HobbiesDto.HobbyId)"
TextField="@nameof(HobbiesDto.HobbyName)"
Placeholder="Select your favourite sport..."
Id="multiselect"
Width="100%"
Rounded="@ThemeConstants.DropDownList.Rounded.Medium"
FillMode="@ThemeConstants.AutoComplete.FillMode.Outline"
TagMode="@MultiSelectTagMode.Single"
ShowClearButton="false">
    <MultiSelectSettings>
        <MultiSelectPopupSettings Height="@CustomThemeConstants.Multiselect.PopupHeight" MaxHeight="@CustomThemeConstants.Multiselect.PopupMaxHeight" />
    </MultiSelectSettings>
</TelerikMultiSelect>

@code {
    public List<int> SelectedHobbyIds { get; set; } = [];

    public IEnumerable<HobbiesDto> Hobbies { get; set; } = new List<HobbiesDto>()
    {
        new HobbiesDto(1, "Basketball"),
        new HobbiesDto(2, "Golf"),
        new HobbiesDto(3, "Baseball"),
        new HobbiesDto(4, "Table Tennis"),
        new HobbiesDto(5, "Volleyball"),
        new HobbiesDto(6, "Football"),
        new HobbiesDto(7, "Boxing"),
        new HobbiesDto(8, "Badminton"),
        new HobbiesDto(9, "Cycling"),
        new HobbiesDto(10, "Gymnastics"),
        new HobbiesDto(11, "Swimming"),
        new HobbiesDto(12, "Wrestling"),
        new HobbiesDto(13, "Snooker"),
        new HobbiesDto(14, "Skiing"),
        new HobbiesDto(15, "Handball"),
    };

    public class HobbiesDto
    {
        public int    HobbyId   { get; set; }
        public string HobbyName { get; set; } = string.Empty;

        public HobbiesDto() { }

        public HobbiesDto(int id, string name)
        {
            HobbyId = id;
            HobbyName = name;
        }
    }
}