### Bug report

The MultiSelect TagHelper is rendered as a DropDownList and does not allow multiple selections.

### Reproduction of the problem

https://demos.telerik.com/aspnet-core/multiselect/tag-helper

### Expected/desired behavior

The MultiSelect TagHelper should allow multiple selections.

### Environment

* **Kendo UI version: 2021.3.914
* **jQuery version: 1.12.4
* **Browser: [all]

Hi

Just to let you know that the Demo for the Grid SignalR feature is showing an error.

(see screen dump attached)

Thanks
Darryl

Bug report

The DatePicker's popup has a CSS min-height property set that causes it to sometimes have an empty blank space at the bottom.

Reproduction of the problem

1. Open the DatePicker Demo
2. Expand the monthpicker

Review another occurence.

Expected/desired behavior

There should be a blank space in the DatePicker's popup.

Environment

• Kendo UI version: 2021.3.914
• Browser: [all]

Bug report

We are trying to prevent users from dropping an image file from their computer directly onto the Editor with Firefox. When this happens the browser converts the image into a uri encoded version of the image. When we define a custom PasteCleanup function to handle this, the Editor will sometimes work as expected but other times it will throw an error when trying to execute the function. This seems to be random after each page load.

Reproduction of the problem

1. Open this Dojo with Firefox
2. Run the Dojo and drag and drop an image from your machine

Please note that the reproduction of the error is inconsistent. However the CustomPasteCleanUp doesn't prevent the addition of the image, nor does the prevention of the Drop event.

Screen capture of reproduction in ASP .NET Core.
Screen capture of reproduction in Dojo.
More information about issue and reproduction available in ticket: 1534730

Current behavior

An image file that is dragged and drop by the user to the Editor is always added to the widget.

Expected/desired behavior

The current behavior should be preventable and an error must not occur.

Environment

• Kendo UI version: 2021.2.616
• Browser: [ Chrome 93 | Firefox 92 ]

Hi Kendo Team,

I am working on Kendo UI ASP.NET Core Grid binding with SignalR. But while starting Hub and providing the Promise, I am facing an error "The "promise" option must be a Promise."

I am following this URL for reference: https://demos.telerik.com/aspnet-core/grid/signalr .

Checked on your website as well, but the issue is also coming there. Here is the URL: https://docs.telerik.com/kendo-ui/api/javascript/data/datasource/configuration/transport.signalr

In this link, when clicking on "Open In Dojo" button, it opens a new window, then clicks on the Run button. It will generate an error in the console "Uncaught Error: The "promise" option must be a Promise.". 

Please check the attached snapshot.

Please reply asap. Thanks in advance!

Bug report

In Core when the ComboBoxFor helper is used as an editor in a Grid (Shared/EditorTemplates) and its Name is set, the Grid does not render and no exception is displayed, to indicate that the Name option should not be set.

Reproduction of the problem

Reproducible in the Editing custom editor Grid demo.

1. Set the ComboBox' Name in the ClientCategory.cshtml template

@(Html.Kendo().ComboBoxFor(m => m)
    .Name("CategoryID")
    .DataValueField("CategoryID")
    .DataTextField("CategoryName")
    .BindTo((System.Collections.IEnumerable)ViewData["categories"])
)

Current behavior

We throw an exception when the Name is set (e.g. if the ComboBox is used outside of a Grid), but in this scenario it is not displayed.

Expected/desired behavior

An exception is thrown and its message is displayed.

Environment

• Kendo UI version: 2019.2.619
• jQuery version: x.y
• Browser: [all]

Bug report

The OrderId field for the Gantt tasks cannot be defined in its datasource using the UI for ASP.NET Core wrappers.

*for more details, please refer to ticket #1461758

Reproduction of the problem

Create a UI for ASP.NET Core project and try to initialize the Gantt component with a datasource configured similar to the following:

Current behavior

The marked "OrderID" definition is not a valid one in UI for ASP.NET Core

Expected/desired behavior

The datasource configuration provided above(or similar) should be valid for the Gantt component. The OrderID should be configurable using the ASP.NET Core wrappers.

Environment

• Kendo UI version: 2020.1.406
• jQuery version: x.y
• Browser: [all]

Bug report

DateRangePicker close event does not catch range ent value

Reproduction of the problem
Run the following Dojo:

• https://dojo.telerik.com/ugAPotiQ

Select a range and check the browser console.

Expected/desired behavior
Close shall be reflected in the close event handler.

Environment
Kendo UI version: [ all ]
Browser: [ all ]

Steps to reproduce:

Open the ASP.NET Core ImageEditor Demo at https://demos.telerik.com/aspnet-core/imageeditor

1. Load a Portrait image (Width < Height)
2. Select the Crop tool
3. Click on Landscape
4. Select any aspect ratio, for example 16:9
5: Select "Original ratio" back again

Current Behavior:

The browser takes some time to respond and sometimes crashes. And each time, we get a stack overflow logged in the browser's Dev Tools - See picture below.

Please correct, it's starting to get a little annoying. The ImageEditor is quite buggy and not usable as is in production. Thanks for your comprehension.

Bug report

PanelBar's TagHelper item url property incorrectly loads content instead of redirecting in v. 2021.2.616

Reproduction of the problem

1. Create a project that uses Kendo version 2021.2.616
2. Initialize the following PanelBar with TagHelper:

    <kendo-panelbar name="panelbar1" class="k-scrollable" style="font-size:smaller" expand-mode="single">
        <items>
            <panelbar-item name="item1" text="First Item (/Index)" url="/Index" />
            <panelbar-item name="item1" text="Second Item (/Privacy)" url="/Privacy" />
            <panelbar-item name="item2" text="Third Item (Telerik demos)" url="https://demos.telerik.com/aspnet-core/"/>
        </items>
    </kendo-panelbar>

3. Compare with the PanelBar with HtmlHelper:

      @(Html.Kendo().PanelBar()
                  .Name("panelbar")
                  .ExpandMode(PanelBarExpandMode.Single)
                  .Items(panelbar =>
                  {
                      panelbar.Add().Text("First Item (/Index)").Url("/Index");
                      panelbar.Add().Text("Second Item (/Privacy)").Url("/Privacy");
                      panelbar.Add().Text("Third Item (Telerik demos)").Url("https://demos.telerik.com/aspnet-core/");
                  })
            )

Current behavior

The Url property of the TagHelper loads content instead of redirecting.

Expected/desired behavior

The Url property should redirect and not load content.

Environment

• Kendo UI version: 2021.2.616
• Browser: [all]

Bug report

When the FileManager is defined using TagHelpers the defined schema is not serialized

Reproduction of the problem

The following FileManager definition:

<kendo-filemanager name="filemanager" upload-url="@Url.Action("FileManagerUpload", "FileManager")">
    <filemanager-datasource>
        <transport>
            <read url="@Url.Action("FileManagerRead", "FileManager")" type="POST" />
            <create url="@Url.Action("FileManagerCreate", "FileManager")" type="POST" />
            <destroy url="@Url.Action("FileManagerDestroy", "FileManager")" type="POST" />
            <update url="@Url.Action("FileManagerUpdate", "FileManager")" type="POST" />
        </transport>
        <schema>
            <filemanager-model id="path" has-children="hasDirectories">
                <fields>
                    <field name="path" type="string" from="Path"></field>
                    <field name="name" type="string" from="Name"></field>
                    <field name="extension" type="string" from="Extension"></field>
                    <field name="created" type="date" from="Created"></field>
                    <field name="createdUtc" type="date" from="CreatedUtc"></field>
                    <field name="modified" type="date" from="Modified"></field>
                    <field name="modifiedUtc" type="date" from="ModifiedUtc"></field>
                    <field name="size" type="number" from="Size"></field>
                </fields>
            </filemanager-model>
        </schema>
    </filemanager-datasource>
    <toolbar>
        <items>
            <item name="createFolder" />
            <item name="upload" />
            <item name="sortDirection" />
            <item name="sortField" />
            <item name="changeView" />
            <item name="spacer" />
            <item name="details" />
            <item name="search" />
        </items>
    </toolbar>
</kendo-filemanager>

generates the following script, without a schema definition:

<script> 
  kendo.syncReady(function() {
    jQuery("#filemanager").kendoFileManager({
        "uploadUrl": "/FileManager/FileManagerUpload",
        "toolbar": {
            "items": [{
                "name": "createFolder"
            }, {
                "name": "upload"
            }, {
                "name": "sortDirection"
            }, {
                "name": "sortField"
            }, {
                "name": "changeView"
            }, {
                "name": "spacer"
            }, {
                "name": "details"
            }, {
                "name": "search"
            }]
        },
        "dataSource": {
            "schema": {
                "model": {
                    "id": "path",
                    "hasChildren": "hasDirectories"
                }
            },
            "transport": {
                "destroy": {
                    "type": "POST",
                    "url": "/FileManager/FileManagerDestroy"
                },
                "read": {
                    "type": "POST",
                    "url": "/FileManager/FileManagerRead"
                },
                "update": {
                    "type": "POST",
                    "url": "/FileManager/FileManagerUpdate"
                },
                "create": {
                    "type": "POST",
                    "url": "/FileManager/FileManagerCreate"
                }
            }
        }
    });
}); 
</script>

Expected/desired behavior

The FileManager DataSource schema should be serialized

Environment

• Kendo UI version: 2021.2.616
• Browser: [all]

### Bug report

The attributes set through the "HtmlAttributes", "ContentHtmlAttributes", and "LinkHtmlAttributes"methods are not applied to the TreeView items.

### Reproduction of the problem

1. Create a TreeView and set attributes by using the "HtmlAttributes", "ContentHtmlAttributes", "LinkHtmlAttributes"methods:

@(Html.Kendo().TreeView()
    .Name("treeview-kendo2")
    .Items(treeview =>
    {
        treeview.Add().Text("My Documents")
        .SpriteCssClasses("k-icon k-i-globe")
        .Expanded(true)
        .Url("/")
        .HtmlAttributes(new { @class = "fairydust1" })
        .ContentHtmlAttributes(new { data_navigate = "navigate_content", @class = "trigger", title = "content_title" })
        .LinkHtmlAttributes(new { data_navigate = "navigate_link", @class = "trigger", title = "content_link" });
    })
)

2. Run the page and inspect the TreeView item.

### Expected/desired behavior

The attributes are serialized and rendered.

### Environment

* **Kendo UI version: 2021.2.616
* **jQuery version: 1.12.4
* **Browser: [all]

Bug report

The PanelBar for Telerik UI for ASP.NET Core and the PanelBar for Telerik UI for ASP.NET MVC HTML helper behaves differently and renders different markup for the same configuration.

Reproduction of the problem

When the the following configuration is used

@(Html.Kendo().PanelBar()
                .Name("panelbar")
                .ExpandMode(PanelBarExpandMode.Multiple)
                .Items(panelbar =>
                {
                    panelbar.Add().Text("Index").Action("Index", "Home");
                    panelbar.Add().Text("Other Pages")
                        .Items(other =>
                        {
                            other.Add().Text("About").Action("About", "Home");
                            other.Add().Text("Contact").Action("Contact", "Home");
                        });
                })
    )

the following markup and initialization script are generated for Telerik UI for ASP.NET MVC:

<ul class="k-widget k-panelbar k-reset" id="panelbar">
   <li class="k-item k-state-default"><a class="k-link k-header" href="/">Index</a></li>
   <li aria-expanded="true" class="k-item k-state-active">
      <span class="k-link k-header">Other Pages<span class="k-icon k-panelbar-collapse k-i-arrow-60-up"></span></span>
      <ul aria-hidden="false" class="k-group">
         <li class="k-item k-state-default"><a class="k-link" href="/Home/About">About</a></li>
         <li class="k-item"><a class="k-link k-state-selected" href="/Home/Contact">Contact</a></li>
      </ul>
   </li>
</ul>
<script>
kendo.syncReady(function(){jQuery("#panelbar").kendoPanelBar({"expandMode":"multiple"});});

and for Telerik UI for ASP.NET Core

<ul class="k-widget k-panelbar k-reset k-header" id="panelbar" data-role="panelbar" tabindex="0" role="tree">
      <li class="k-item k-state-default k-first" role="treeitem"><a class="k-link k-header" href="/">Index</a></li>
      <li class="k-item k-state-default k-last" aria-expanded="false" role="treeitem">
         <span class="k-link k-header">Other Pages<span class="k-icon  k-panelbar-expand k-i-arrow-60-down"></span></span>
         <ul class="k-group k-panel" style="display:none" role="group" aria-hidden="true">
            <li class="k-item k-state-default k-first" role="treeitem"><a class="k-link" href="/Home/About">About</a></li>
            <li class="k-item k-state-default k-last" role="treeitem" aria-selected="true"><a class="k-link k-state-selected" href="/Home/Contact">Contact</a></li>
         </ul>
      </li>
   </ul>
   <script>kendo.syncReady(function(){jQuery("#panelbar").kendoPanelBar({"autoBind":true,"loadOnDemand":true,"expandMode":"multiple"});});</script>

Current behavior

Besides the different markup the component behaves differently - navigating to the Contact page with the above configuration results in the PanelBar for Telerik UI for ASP.NET MVC being expanded and the Contact Child item selected, but the the PanelBar for Telerik UI for ASP.NET Core is collapsed and the selected item is not visible.

Expected/desired behavior

The PanelBar should behave the same way in the Telerik UI for ASP.NET MVC and Telerik UI for ASP.NET Core suites.

Environment

• Kendo UI version: 2021.2.616
• Browser: [all]

Kendo dialog structure doesn’t use Aria landmarks properly for buttons  - this leads to a validation error

The pager control's select box renders role="listitem" but the parent is missing role="list"  - this leads to a validation error

Listviews will render role="list" even when empty - this leads to a validation error

Kendo grids use 2 tables (one for header and one for the data) which means that there are no role="cell" assigned to any of the headers  - this leads to a validation error

Scrollable grids are missing a tabindex="0" to allow for keyboard navigation - this leads to a validation error

this form doesn't have Core 2, 2.1, 3.0, 3.1 or 5 in the .Net Framework drop down. Just gonna pick 4.8 even though it doesn't apply. I am using core 5.

Bug report

When the setOptions of the Slider is applied with or without parameters the navigation of the Slider with the mouse breaks unless the resize() method is called immediately after.

Reproduction of the problem

1. Open this Dojo
2. Click the Without resize button
3. Navigate the Slider with the mouse

Note that even if the With resize button is subsequently clicked the behavior persists

Current behavior

Slider.setOptions() breaks mouse navigation of the Widget

Expected/desired behavior

Slider.setOptions() should call the resize method internally to prevent the issue

Environment

• Kendo UI version: 2021.2.616
• Browser: [all ]

Bug report

When a Telerik UI Window is draggable and has its Position set, the first time the widget can be dragged, or it is being dispositioned while dragging.

Reproduction of the problem

1. Create a Telerik Window widget.

2. Set the Position.Left and Position.Top

3. Open and drag the window.

Expected/desired behavior

The window should be smoothly draggable.

Environment

* **Kendo UI version:** 2021.2.511
* **jQuery version:** 1.12.4
* **Browser:** [all]

Bug report

Setting the HeaderHtmlAttributes of the TreeList throws a Null reference exception.

Reproduction of the problem

1. In the Multi-column headers Demo of the Treelist try adding HeaderHtmlAttributes to a Group:

@(Html.Kendo().TreeList<Kendo.Mvc.Examples.Models.TreeList.EmployeeDirectoryModel>()
        .Name("treelist")
        .Columns(columns =>
        {
            columns.Group(group => group
                .Title("Personal Info")
                .HeaderHtmlAttributes(new {@class="myClass"})
                .Columns(info =>
                {
                  //...
                })
            );
        })

Current behavior

Null reference exception is thrown.

Expected/desired behavior

The Html attributes should be added to the header.

Environment

• Kendo UI version: 2021.2.616
• Browser: [all]

Bug report

The DataSource's property groupPaging: true prevents the Grid's group from expanding if it has a defined groupHeaderColumnTemplate.

Reproduction of the problem

1. Open this Dojo
2. Try to expand the Grid's groups

Also reproducible in the Core wrapper where an error is thrown: kendo.all.js:8743 Uncaught TypeError: Cannot read property 'hasSubgroups' of undefined

Current behavior

groupPaging is not compatible with the groupHeaderColumnTemplate

Expected/desired behavior

groupPaging and the groupHeaderColumnTemplate should be compatible

Environment

• Kendo UI version: 2021.2.616

• Browser: [all]

Steps to reproduce:

1. Open an image
2. Select the crop tool.
3. Resize the crop to a smaller area.
4. Move the crop area to the top middle of the image for example.
5. Resize the crop to a larger area using the bottom right handle.

Current behavior:

The crop area overflows the image if it is made large enough.

The problem is also reproducible on Telerik Demos at https://demos.telerik.com/aspnet-core/imageeditor

C# / .NET 5 / Telerik.UI.for.AspNet.Core (V2021.2.511)

### Bug report

The Telerik UI ListBox is not being rendered when the AutoBind() option is specified. Regardless of the value that is put inside the method - be it true/false.

### Reproduction of the problem

1. Set the DataSource option of the ListBox without specifying type such as Ajax/Custom.

2. Set the AutoBind(true) option.

3. Run the application - the page is not rendered at all.

### Expected/desired behavior

The widget should be rendered when the AutoBind is set to true/false.

### TicketID: 1524780

### Possible reason for the behavior

When the Ajax/Custom type of the data source is not specified, the type defaults to null. Hence, there is a boolean property that is checked inside the VerifySettings method of the ListBox.cs file in the source. The IsClientBinding property checks if the widget is bound to a data source, however, since the data source does not have a type, it thinks that the widget is bound to the data via the BindTo option which is incorrect. 

Having the AutoBind() property and the BindTo() property enabled, a C# error is thrown inside the VerifySettings() method. However, this error should not be thrown when a data source is specified (even without type).

### Environment

* **Kendo UI version:** 2021.2.616
* **jQuery version:** 1.12.4
* **Browser:** [all]