Bug report

When a PDF file that contains PNG images is loaded in the PDFViewer that uses DPL, the PNG files are not displayed in the viewer.

Reproduction of the problem

1. Open this project(PDFViewerDPL.zip) and run it

Current behavior

An empty file loads in the PDFViewer while the loaded PDF file contains the logo of the Firefox browser.

Expected/desired behavior

The PDFViewer should display the Firefox logo loaded in the PDF file.

Environment

• Kendo UI version: 2020.3.1021
• jQuery version: x.y
• Browser: [all]

Bug report

Problem with ToTreeDataSourceResult method when filtering on root and child level.

Also applying filtering causes a significant slowdown in the query created by the ToTreeDataSourceResult method even when applied to small datasets.

Reproduction of the problem

Please refer to the code below and simply filter the first column with the value of 5.

//View
@(Html.Kendo().TreeList<WebApplication1.Models.SerialModel>()
        .Name("treelist")
         .Toolbar(toolbar => toolbar.Create().Text("New Level"))
        .Columns(columns =>
        {
            columns.Add().Field(e => e.RecordID).Width(280);
            columns.Add().Field(e => e.SerialNumber).Width(160);
            columns.Add().Field(e => e.Name);
            columns.Add().Field(e => e.Location).Width(200);
            columns.Add().Field(e => e.ParentID).Width(140);
            columns.Add().Command(c =>
            {
                c.CreateChild().Text("New Child");
                c.Edit();
                c.Destroy();
               
            }).Width(250);
        })
        .Editable(editable => editable.Mode("inline")).Filterable(true).Filterable(f => f.Extra(false))
        .DataSource(dataSource => dataSource
            .Read(read => read.Action("TreeListData", "Home"))
            //.ServerOperation(false)
            .Model(m =>
            {
                m.Id(f => f.RecordID);
                m.ParentId(f => f.ParentID).DefaultValue("0");
                
            })
        )
        .Height(540)
)

//Controller code: 
public ActionResult TreeListData([DataSourceRequest]DataSourceRequest request, int? id)
        {
            var source = Enumerable.Range(1, 5).Select(x => new SerialModel()
            {
                RecordID = x,
                SerialNumber = x,
                Name = "Name " + x,
                Location = "Location " + x,
                hasChildren =  true,
                ParentID = x < 5 ? 0 : (x / 5)
            });
            return Json(source.ToTreeDataSourceResult(request, e => e.RecordID,
                e => e.ParentID, e => id.HasValue ? e.ParentID == id : e.ParentID == 0, m => m));
        }

Expected/desired behavior

Instead of 1 record it returns 2 same items.

Filtering of the TreeList should be as fast as sorting.

Environment

• Kendo UI version: 2023.1.117

Issue

Using any overload of ToDataSourceResult(Async) with a DataSourceRequest containing filter descriptors on an IQueryable provided by Entity Framework core 2.x, causes Entity Framework's "Query cache" to fill up for different filter values, leaking memory in the process. This is caused by using Expression.Constant in the generated expression trees for a DataSourceRequest's FilterDescriptors. Refer to https://github.com/dotnet/efcore/issues/14859 for more details about why this leaks memory.

Since Entity Framework's cache is always missed for new filter values, performance is also degraded due to this issue.

The issue is not present when using Entity Framework core 3 or greater. Apparently using Expression.Constant is not an issue on these version.

I have attached a minimal working example that illustrates the memory leak.

Fix

This issue can be fixed by changing FilterDescriptorExpressionBuilder.CreateValueExpression to not return a ConstantExpression, but a MemberExpression instead. Entity Framework 2.x will correctly parameterize the MemberExpression, causing the query cache to be hit correctly for queries that only differ in parameter values. It won't parameterize ConstantExpressions. Refer to https://stackoverflow.com/a/60516780/147993 for an example of generating a MemberExpression instead of a ConstantExpression.

Bug report

Reproduction of the problem

1. Open the Dojo - https://dojo.telerik.com/FcHfotEy
2. Hover over more than one image

Current behavior

Only the first image has the correct width and height

Expected/desired behavior

The Tooltip should respect the width and height size configurations.

Workaround:

contentLoad: function (e) {
              $(".k-tooltip.k-popup").width(500).height(500);
            },

https://dojo.telerik.com/lvXLxxYD 

TicketID: 1717434

The issue is a regression starting with 2026.2.520 version

Environment

• Kendo/Telerik version: 2026.2.520
• Browser: [all ]

Bug report

Grid throws an error when there are double quotes in foreign key column values:

new TestSelectItem { Text = "AAA\"BBB\"CCC", Value = "2" },

Reproduction of the problem

1. Open and run the attached sample projectBadQuotes_sample.zip
2. Click ‘Add’ button

Current behavior

The following error is thrown in the console:

SyntaxError: Failed to execute 'appendChild' on 'Node': Unexpected identifier 'My' (at VM20:1:144)

Expected/desired behavior

There should be no error and the value should appear escaped:

Workaround:

Text = item.Text?
    .Replace("\\", "\\\\")
    .Replace("\"", "\\\"")

TicketID: 1717693

The issue is a regression starting with Ui for ASP.NET Core version 2024.4.1112

Environment

• Kendo/Telerik version: 2026.3.811
• Browser: [all ]

Bug report

Button 'New Event' don't translate after change language:

Environment

• Kendo/Telerik version: 2026.3.811
• jQuery version: x.y
• Browser: [all]

Using the latest 2026.3.811 version produces the following errors:

• kendo.all.d.ts(12072,26): error TS2552: Build:Cannot find name 'SchedulerKendoKeydownEvent'. Did you mean 'SliderKendoKeydownEvent'?
• kendo.all.d.ts(14372,9): error TS2416: Build:Property 'options' in type 'ToggleButton' is not assignable to the same property in base type 'Button'.
• kendo.all.d.ts(14384,15): error TS2430: Build:Interface 'ToggleButtonOptions' incorrectly extends interface 'ButtonOptions'.

Bug report

Reproduction of the problem

1. Open the Dojo - https://dojo.telerik.com/zjwPGXDx/3
2. Click → Open Window 1 → Open Window 2 → Open Payroll Window
3. In the Add Payroll change a value and click Save

Current behavior

The Dialog is displayed below Kendo Widnow although the .open() method is used which should invoke .toFront()

Expected/desired behavior

As the Dialog is the last opened Dialog/Window it should be displayed over the Window

TicketID: 1717764

Workaround:

setTimeout(function(){              
              kdAddPayrollError.open();
            }, 500)

Dojo - https://dojo.telerik.com/cxXRIZgS

The issue is a regression starting with: 2025.4.1217

Environment

• Kendo/Telerik version:
• jQuery version: x.y
• Browser: [all | Chrome XX | Firefox XX | IE XX | Safari XX | Mobile Chrome XX | Android X.X Web Browser | iOS XX Safari | iOS XX UIWebView | iOS XX WKWebView ]

Bug report

Reproduction of the problem

1. Run this dojo - https://dojo.telerik.com/rGSjmlhv/2
2. Filter Discontinued - true - > shows all items with value true (correct)
3. Filter Discontinued - false → shows all items with value false (correct)
4. Filter Discontinued - true - > shows empty (incorrect)

TicketID:

1718475

Environment

• Kendo/Telerik version: 2026.3.811
• jQuery version: 3.7.0

Bug report

The DropDownList stretches to adapt to the length of the selected item.

Reproduction of the problem

1. Run this Dojo
2. Change the selected item

Expected/desired behavior

The width of the DropDownList should be consistent.

Environment

• Kendo UI version: 2023.1.314

Bug report

Reproducible in Chrome and Firefox. Not reproducible in IE11.

Reproduction of the problem

Dojo example.
There are two Menus. In the first one navigation is triggered from the function passed to the "Sub Item 2" item's url option. In the second Menu navigation is triggered in the Menu's select event handler.

1. Hover "Item 2" and click "Sub Item 2"
   The wiki page will open in a new tab.
2. Check the Menu in the original tab with the dojo.

Current behavior

Doing this in the first Menu, results in the submenu remaining open.

Expected/desired behavior

The submenu should close in both scenarios, since closeOnClick is enabled by default and the select event fires before triggering the navigation.

Environment

• Kendo UI version: 2020.1.114
• jQuery version: x.y
• Browser: [Chrome XX | Firefox XX]

Hello,

On Chrome for Android, the dropdown menu appears offscreen. With Firefox for Android or Chrome desktop, it works well.
This sample reproduces the problem : https://runner.telerik.io/fullscreen/@kakone/azuPAHuy. If you click on the right item (user icon), the dropdown appears offscreen.

Hello Team,

when I add new folder then I rename it to 1.1 it show me 1.1.1 but the folder name is 1.1 and in properties 1.1 but I don't want it to show 1.1.1

the file manager add .1 automatically and if I rename it 2.2 it add .2 then the file display name 2.2 .

Please help,

Thank you,

Bug report

Reproduction of the problem

TelerikAspNetCoreApp98.zip

1. Run the attached project.
2. Focus the MultiSelect and type in "bu". The data is filtered and items matching the filter are displayed in the list.
3. Select the first item in the list
4. Type in "bu" again. The list shows the first "bu" item as selected (expected)
5. Scroll down the list, so that another page of the data is loaded
6. Now scroll up to the first item

Current behavior

The item is no longer highlighted as selected.

Expected/desired behavior

The item is highlighted as selected.

Environment

• Kendo UI version: 2020.2.513
• jQuery version: x.y
• Browser: [all]

Bug report

Related to daylight saving: in the US on14 March, 2021, at 2:00AM the clocks are moved 1h forward.

Reproduction of the problem

Dojo example.

1. Set the computer's timezone to Pacific (US/Canada).
2. Double click the 2:00AM or the 2:30AM slot to add a new event.

Current behavior

The selection is moved 1h back to 1:00AM (or 1:30AM respectively) and the event is created at this time.

Expected/desired behavior

The event should be created at 3:00AM. This will be consistent with the way Outlook handles daylight saving - in a new meeting if you select 2:00AM as a start time, it is automatically changed to 3:00AM.

Environment

• Kendo UI version: 2021.1.224
• jQuery version: x.y
• Browser: [Chrome 88, IE11]

I have a screen that I'm manually calling the print functionality of the kendo-pdfviewer from a button click.   It is working, but the problem is that the resulting print dialog window is really small.   Even if I open the print dialog, resize the dialog, and then try to print again it gets reset to the original small size.  This is preventing our users from previewing what the resulting page will print like.   



This is the code for my pdf viewer

<div class="row">
    <div class="col">

        <div id="example">

            <kendo-pdfviewer name="pdfviewer" height="300">
                <pdfjs-processing file="@(Url.Page("/Badges/Details", "VisitorBadge", new { BadgeId = @Model.Id }))" />
                <toolbar enabled="false">
                    <pdfviewer-toolbar-items>
                        <pdfviewer-toolbar-item command="PrintCommand" type="button" name="print" icon="print"></pdfviewer-toolbar-item>
                    </pdfviewer-toolbar-items>
                </toolbar>
            </kendo-pdfviewer>
        </div>

        <style>
            html body #pdfviewer {
                width: 100% !important;
            }
        </style>
    </div>
</div>

    badgereport.onWindowOpen = function () {
        $pdfviewer = $("#pdfviewer").data("kendoPDFViewer");
        $printBadgePdf = $("#printBadgePdf");
        $closeBadgePdf = $("#closeBadgePdf");
        $badgeWindow = $("#badgeWindow").data("kendoWindow");

        $printBadgePdf.on("click", function (e) {
            e.preventDefault();
            $pdfviewer.execute({ command: "PrintCommand" });

        });
        $closeBadgePdf.on("click", function (e) {
            e.preventDefault();
            $badgeWindow.close();
        });

    };

Bug report

If a ListItem element contains a margin-left style, the user can not delete the bulleted item.

Reproduction of the problem

1. Go to this Progress Kendo UI Dojo.
2. Using case 1 in the code, attempt to delete a bulleted item using the backspace.
3. Using case 2, only the last bulleted item is using margin-left and will not be able to delete.

Here is a screencast of Case 1 in action.

Expected/desired behavior

The bulleted item should be deleted when the user presses backspace.

Environment

• Kendo UI version: 2020.3.1118
• Browser: all

Bug report

When the pasteHtml command or the paste method is used on a line that only has   or a tag these are deleted.

Reproduction of the problem

1. Run this Dojo
2. Press space a couple of times
3. Click the Add Module button
4. The spaces have disappeared

Alternatively, turn on Bold formatting without typing anything and click the Add Module button. The Bold formatting gets cleared

Expected/desired behavior

Pasting content in the Editor

Environment

• Kendo UI version: 2022.3.802

Bug report

File Manager's toolbar overflow button does not show when the items are marked with the overflow setting.

Reproduction of the problem

1. Run the following dojo.
2. Set the overflow setting for one of the items in the Toolbar.

Current behavior

The overflow button is not displayed when one of the items is configured with the overflow setting.

Expected/desired behavior

The overflow button should be displayed when one of the items is configured with the overflow setting similar to the conventional toolbar widget's items.

Environment

• Kendo UI version: 2022.6.621
• Browser: [all]