Consider the use of TextWriter async methods for the HTML Helpers, for example the WriteInitializationScript methods.  In certain scenarios the use of the synchronous methods causes an exception: System.InvalidOperationException: Synchronous operations are disallowed. Call WriteAsync or set AllowSynchronousIO to true instead.

This can be resolved by explicitly enabling synchronous operations

services.Configure<IISServerOptions>(options =>
    {
        options.AllowSynchronousIO = true;
    });

though synchronous operations have been disabled by default at framework level as of .NET 3.0.

### Bug report

When using the default column checkbox filter menu and the data requested from the server takes time to load, the filter menu popup does not resize correctly when opening the menu for the first time.

The issue started to occur in version 2025.1.211.

### Reproduction of the problem

1) Enable the checkbox filter menu of a specified column. The Grid binds to remote data and the data operations are perfomed on the server.

2) Open the filter menu when the Grid is loaded.

3) The Read request triggers and a loader is displayed to indicate that the data is loading:

4) The options are loaded, but the popup container does not expand as expected:

5) Close the filter menu and opend it again:

### Expected/desired behavior

The filter menu popup must display all options when the data is loaded.

### Workaround

<style>
     .k-animation-container-shown {
        overflow: visible !important;
    }
</style>

### Environment

* **Kendo UI version: 2025.2.520
* **jQuery version: 3.7.1
* **Browser: [all]

### Bug report

When the TreeList is set up for Popup editing, the "required" validation triggers immediately when the Popup form is opened.

### Reproduction of the problem

1) Create a Popup editable TreeList.

2) Add the DataAnnotation [Required] attribute to any of the Model properties.

3) Click the built-in "Add new record" command.

4) The editor of the required field is automatically focused and the validation triggers immediately.

The behavior can be observed in the TreeList Popup Editing demo: https://demos.telerik.com/aspnet-core/treelist/editing-popup

### Expected/desired behavior

The validation must trigger on blur, as in the jQuery demo.

### Environment

* **Telerik UI for ASP.NET Core version: 2025.2.520
* **Browser: [all]

### Bug report

When the virtualization is enabled, in some cases, the selected options in the dropdown do not match the selected options in the input. 

### Reproduction of the problem

1) Create a MultiSelect with Virtualization (for example, the same configuration as in the online demo).

2) Select multiple options from the dropdown.

3) Enter a search entry in the input to filter the displayed options and select a specified option.

4) Scroll down and select another option.

5) Remove some of the already selected options through the input.

6) Open again the dropdown. The selected options in the input do not match the selected options in the dropdown.

A screencast for reproduction: https://app.screencast.com/v6GtyST0dQAnh

### Expected/desired behavior

Bug report

The Form ignores the [Display(Name = "Value")] Data Annotation attribute:
telerik/kendo-ui-core#6503

Reproduction of the problem

The Email Label should read "Message":
https://netcorerepl.telerik.com/wzuDulvO14AtS2vC17

Bug report

When ParseFormats is set in the DatePicker editor used in the Grid popup, the picker does not show the field value to which it is bound.

Reproduction of the problem

1. Add a DateOnly? field to the model:

public DateOnly? OrderDate { get; set; }

2. Bind a Grid column to the field.
3. Set the default value in the DataSource:

.Model(model =>
{
    model.Id(p => p.OrderID);
    model.Field(p => p.OrderDate).DefaultValue(new DateOnly());
})

4. Configure Popup editing in the Grid.
5. Add a DateOnly.cshtml editor in EditorTemplates:

@model DateOnly?

@(Html.Kendo().DatePickerFor(m => m).ParseFormats(new string[] { "MM/dd/yyyy" }).HtmlAttributes(new { title = Html.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName("") }))

Current behavior

When editing a record. The value of the OrderDate field is not displayed in the DatePicker.
If you remove the ParseFormats option from the DatePicker, it shows the value as expected.

Expected/desired behavior

The field value should be displayed in the picker, even when ParseFormats is set.

Environment

• Kendo UI version: 2024.4.1112
• Browser: All

column-command template does not access datasource as an ordinary column template.

<kendo-grid name="grid">
    <columns>
        <column field="ProductID" title="ID" />
        <column title="Column" template="#=columnTemplate(data.ProductID)#" />
        <column title="ColumnCommand">
        <commands>
            <column-command name="change" template="#=columnTemplate(data.ProductID)#"></column-command>
        </commands>
    </column>
    </columns>
    <datasource type="DataSourceTagHelperType.Custom" server-filtering="true">
        <transport>
            <read url="@Url.Action("ServerFiltering_GetProducts", "MultiSelect")" />
        </transport>
    </datasource>
</kendo-grid>

<script>
    function columnTemplate(productID) {
        if (productID % 2 == 0)
            return 'even';
        else
            return 'odd';
    }
</script>

Reproduction of the problem:
https://netcorerepl.telerik.com/myurdlbI16kA1TM213

Current behavior:
There is no way to have a dynamic template for column commands that depends on datasource.

Expected/desired behavior:
Having column-command template as column template, making it possible to access data from datasource.

Environment:
Kendo UI version: 2024.2.514

Workaround:
As an alternative solution, I'm using data-bound event, performing a for loop to all rows, but it needs to go line by line, which is not the best solution for large data.

### Bug report

When building the scripts with NPM, there is syntax error "Unexpected number":

### Reproduction of the problem

Build the scripts (version 2025.3.812).

### Expected/desired behavior

The scripts must be built successfully.

### Workaround:

Remove the extra single quotes that wrap the version in the "rollup.mjs.config.mjs" and "rollup.modules.config.js" files:

• rollup.mjs.config.mjs

import glob from 'glob';
import path from 'path';
import { nodeResolve } from '@rollup/plugin-node-resolve';
import polyfill from 'rollup-plugin-polyfill';
import alias from '@rollup/plugin-alias';

...

const version = '2025.3.812';

• rollup.modules.config.mjs

import glob from "glob";
import path from "path";
import { nodeResolve } from "@rollup/plugin-node-resolve";
import polyfill from "rollup-plugin-polyfill";
import alias from "@rollup/plugin-alias";

...

const version = '2025.3.812';

### Environment

* **Kendo UI version: 2025.3.812

### Bug report

When the Grid is set up for OData-v4 binding, the columns that bind to DateOnly fields fail to filter. The date value in the filter expression contains the time portion and the following error is thrown:

"The binary operator GreaterThan is not defined for the types 'System.Nullable`1[System.DateOnly]' and 'System.Nullable`1[System.DateTimeOffset]'."

### Reproduction of the problem

1) Create a Grid that uses OData-v4 binding.

2) Bind a specified column to a DateOnly field.

3) Filter the column through the default column filter menu and open the browser DevTools to review the response of the request.

//Model
public DateOnly LastProdUpdate { get; set; }

//View
@(Html.Kendo().Grid<ProductViewModel>()
    .Name("grid")
     .Columns(columns =>
        {
            columns.Bound(p => p.LastProdUpdate).Format("{0:dd/MM/yyyy}");
        })
        ...
        .Filterable()
        .DataSource(dataSource => dataSource
        .Custom()
        .Type("odata-v4")
        .Transport(t =>
        {
            t.Read(read => read.Url("/odata/Products").Data("function() {return {'$expand': 'Employee'} }"));
        })
        .PageSize(10)
        .ServerPaging(true)
        .ServerFiltering(true)
        .ServerSorting(true)
     )
)

### Expected/desired behavior

The DateOnly fields must be filtered successfully as the DateTime fields.

### Environment

* **Kendo UI version: 2024.4.1112
* **Browser: [all]

Bug report

Filterable configuration in ForeignKey is not serialized in TagHelper Grid.

Reproduction of the problem

Open this REPL example

Current behavior

Filterable configuration in ForeignKey is not serialized in TagHelper Grid.

Expected/desired behavior

Filterable configuration in ForeignKey should be serialized in TagHelper Grid.

TicketID:

1692361

Environment

• Kendo UI version: 2025.2.702
• Browser: [all]

Currently, the Content function for Steps in a Wizard only accepts a string value (see API here). 
This means that in order to add a partial view (bound to the current model and its properties), the most straightforward way I could find was to put the partial view (and any wrappers) in its own file and add an extension method "ToHtmlString()". For example:

@model MyModel

@(Html.Kendo().Wizard().Steps(step => {
    step.Add().Content(Html.Partial("~/Path/To/View/Wrapper.cshtml", Model).ToHtmlString());
})

using Microsoft.AspNetCore.Html;
using System.IO;

public static class HtmlContentExtensions
{
    public static string ToHtmlString(this IHtmlContent htmlContent)
    {
        if (htmlContent is HtmlString htmlString)
        {
            return htmlString.Value;
        }

        using StringWriter writer = new();
        htmlContent.WriteTo(writer, System.Text.Encodings.Web.HtmlEncoder.Default);
        return writer.ToString();
    }
}

@model MyModel

@(Html.Kendo().TabStrip().Items(tabstrip => {

    tabstrip.Add()
    .Content(@<div id="@Model.TabContainer" class="myTabWrapperClass"> 
       @await Html.PartialAsync("~/Path/To/View.cshtml", Model)
    </div>);

})

Is it possible to implement an option that enables the paging of the Grid View?

For example:

@(Html.Kendo().FileManager()
    .Name("filemanager")
     .Views(gridView => gridView.Grid(grid => grid.Pageable()))
     ...
)

### Bug report

When loading an editor through a partial View using EditorTemplateView(await Html.PartialAsync("PartialViewName")), the following error occurs:

The 'await' operator can only be used within an async lambda expression. Consider marking this lambda expression with the 'async' modifier.

### Reproduction of the problem

@(Html.Kendo().Form<UserViewModel>()
     .Name("myForm")
     .Items(items =>
     {
         items.Add().Field(f => f.Username).EditorTemplateView(await Html.PartialAsync("PartialViewName"));
      })
)

### Expected/desired behavior

The EditorTemplateView() must accept Html.PartialAsync("PartialViewName").

### Environment

* **Telerik UI for ASP.NET Core version: 2024.4.1112
* **Browser: [all]

### Bug report

When setting autoWidth: true and expanding a node, the popup's width is not adjusted based on the displayed child nodes.

### Reproduction of the problem

1) Enable the autoWidth option and open the DropDownTree.

2) Expand an item. A horizontal scrollbar appears and the width of the popup is not adjusted as expected:

A Dojo sample for reproduction: https://dojo.telerik.com/faeuFFwb/2

### Expected/desired behavior

The width of the popup must be automatically adjusted when expanding an option and the "autoWidth" option is enabled.

### Environment

* **Kendo UI version: 2025.2.702
* **jQuery version: 3.7.1
* **Browser: [all]

### Bug report

When dragging and dropping a file into a specified FileManager folder, the Upload request triggers twice.

### Reproduction of the problem

1. Open the FileManager Demo: https://demos.telerik.com/kendo-ui/filemanager/index

2. Open the browser's Network tab.

3. Drag and drop a file into the FileManager.

4. Two Upload requests are triggered one after another.

### Expected/desired behavior

When uploading a single file with drag & drop, a single Upload request must trigger. When using the default upload button to upload a file, a single request triggers as expected.

### Environment

* **Kendo UI version: 2024.4.1112
* **jQuery version: 3.7.1
* **Browser: [all]

### Bug report

When defining custom editors in the OrgChart form by using EditorTemplateView() or EditorTemplateId() options, the editors are not initialized as expected.

### Reproduction of the problem

1) Define a DropDownList editor in a partial View and load it through the EditorTemplateView() option:

@(Html.Kendo().OrgChart<OrgChartEmployeeViewModel>()
                .Name("departmentsChart")
                .Editable(edit =>
                {
                    edit.Form(form => form
                      .Items(i =>
                      {
                         i.Add().Field(x => x.ParentDepartment).EditorTemplateView(Html.Partial("~/Views/Shared/EditorTemplates/ParentDepartmentDropDown.cshtml"));
                      }));
                })
                ...
)

// ~/Views/Shared/EditorTemplates/ParentDepartmentDropDown.cshtml
@model OrgChartEmployeeViewModel

@(Html.Kendo().DropDownListFor(m => m.ParentDepartment)
    .OptionLabel("-None-")
    .DataTextField("Text")
    .DataValueField("Value")
    .DataSource(source =>
    {
	    source.Read(read => read.Action("ReadDepartments", "Home"));
    })
)

2) The DropDownList is not initialized when opening the OrgChart form.

### Expected/desired behavior

The editors defined through the EditorTemplateView() or EditorTemplateId() options must be initialized correctly.

### Environment

* **Kendo UI version: 2025.2.520
* **jQuery version: 3.7.1
* **Browser: [all]

Bug report

TimeDurationPickerFor does not work in EditorTemplates scenarios.

Reproduction of the problem

1. Create a TimeDurationPickerFor Helper within a standalone view within the ~/Views/EditorTemplate/ folder.

@model double

@(Html.Kendo().NumericTextBoxFor<double>(m => m))

2. Use the Editor template within a more compound component. E.g the Grid

        .Columns(columns =>
        {
            columns.Bound(m => m.Duration).EditorTemplateName("TimeDurationPicker");
            columns.Command(command => command.Edit());
        })

3. Notice that the application produces a server error.

Current behavior

The TimeDurationPickerFor Helper does not work in EditorTemplates scenarios.

Expected/desired behavior

The TimeDurationPickerFor Helper should work in EditorTemplates scenarios.

Environment

• **Kendo UI version: 2025.2.702
• **Browser: [all]