Last Updated: 20 Nov 2019 10:44 by ADMIN

Bug report

When a custom class attribute is set via the columns.attributes option, the TreeList renders an additional class that is undefined.

Reproduction of the problem

1. Initialize a TreeList.

2. Set a custom class via the attributes option:

3. Inspect the relevant "td" element

Dojo sample for reproduction:


Expected/desired behavior

The TreeList should render only the specified classes.


* **Kendo UI version:** 2019.3.1023
* **jQuery version:** 1.12.4
* **Browser:** [all] 

Last Updated: 05 Aug 2019 11:11 by ADMIN
Release 2019.R3
Created by: Eduard Töws
Comments: 2
Category: Kendo UI for jQuery
Type: Bug Report

Bug report

An error occurs on components' initialization when using a custom Kendo UI build which includes PDFviewer

Reproduction of the problem

  1. Go to Kendo UI Custom Download page
  2. In the "WEB" section select random components including the Grid and PDFviewer
  3. Download the custom build(kendo.custom.min.js file) and put it in the same folder with an HTML file with the following structure.
<!DOCTYPE html>

        html {
            font-size: 14px;
            font-family: Arial, Helvetica, sans-serif;
    <link rel="stylesheet" href="https://kendo.cdn.telerik.com/2019.2.514/styles/kendo.default-v2.min.css" />

    <script src="https://kendo.cdn.telerik.com/2019.2.514/js/jquery.min.js"></script>
    <script src="./kendo.custom.min.js"></script>

    <div id="example">
        <div id="grid"></div>
            $(document).ready(function () {
                    dataSource: {
                        type: "odata",
                        transport: {
                            read: "https://demos.telerik.com/kendo-ui/service/Northwind.svc/Customers"
                        pageSize: 20
                    height: 550,
                    groupable: true,
                    sortable: true,
                    pageable: {
                        refresh: true,
                        pageSizes: true,
                        buttonCount: 5
                    columns: [{
                        template: "<div class='customer-name'>#: ContactName #</div>",
                        field: "ContactName",
                        title: "Contact Name",
                        width: 240
                    }, {
                        field: "ContactTitle",
                        title: "Contact Title"
                    }, {
                        field: "CompanyName",
                        title: "Company Name"
                    }, {
                        field: "Country",
                        width: 150
  1. The following error appears:
    Uncaught TypeError: Cannot read property 'Toolbar' of undefined

Current behavior


Expected/desired behavior

A Grid should be initialized properly and without errors if a custom build is including the PDFviewer


  • Kendo UI version: 2019.2.514
  • jQuery version: x.y
  • Browser: [all]
Last Updated: 08 Mar 2019 15:21 by ADMIN
Created by: DDL
Comments: 0
Category: Kendo UI for jQuery
Type: Bug Report

When a ContextMenu is opened for the first time, the animation is not executed. Every consequent open trigger the animation successfully.

The issue can be observed in the following Dojo.

Steps to reproduce:

  • Open the ContextMenu and notice there is no animation.
  • Open the ContextMenu again and notice the default animation is triggered.

Last Updated: 03 Feb 2020 19:37 by Daewoong
Created by: Daewoong
Comments: 0
Category: Kendo UI for jQuery
Type: Bug Report

Describe the bug
Once the Tooltip is shown for a target with short title, if opened for a target with longer title, its width is not updated properly. The shortest width is persisted. Reproducible in all SASS themes, not reproducible in the LESS themes.

To reproduce
Steps to reproduce the behavior:

  1. Go to dojo.
  2. Hover "Korean"
  3. Hover "Korean short"
  4. Hover "Korean" again

Expected behavior
The Tooltip should resize properly to fit the title of the element it is shown for.


Affected package (please provide)

  • theme-default
  • theme-bootstrap
  • theme-material

Affected suites (please provide)

  • Kendo UI for jQuery
  • Kendo UI for Vue

Affected browsers (please provide)

  • Firefox: [latest]
  • Chrome: [latest]
  • Edge version: [latest]
  • IE version: [11]

Build system information (please provide)

  • OS: [Windows]

Additional context

Need More Info
Last Updated: 21 Jan 2020 12:05 by ADMIN
Created by: Rahini
Comments: 3
Category: Kendo UI for jQuery
Type: Bug Report

Hi Team,


Sorry for the confusion. I don't know where to post this content issue I saw in your website.

Have a nice day :)


In Development
Last Updated: 05 Jan 2021 09:52 by ADMIN

If the delete rows button is used on a table that is followed by another table, and all the rows from the first one are deleted, the next table receives focus. Upon clicking the delete row button again, an error is being thrown "Cannot read property 'rows' of undefined".

The issue can be reproduced with the Basic Usage Demo::

  • create a table
  • create a table immediately following the first
  • focus the last row of the first table and click the 'Delete row' button until all rows are deleted.
  • Click the 'Delete row' button again.

Last Updated: 15 Mar 2019 06:19 by ADMIN

In a grid with virtualization, when just normally scrolling down requests for the exact same data are often sent multiple times after each other. The reason for this is probably that the grid sends an asynchronous request for example Top 100, Skip 200 and then does not keep track of that it is still waiting for a reply for this request, before asking for the same data a short period later. 

Commonly requests for the same data is made 2 or 3 or more times after each other, causing performance problem at the server side and in many cases unnecessary calls to the database. Fixing this should lower the number of requests for data to the server considerably, maybe with a factor two or more with just normal grid operation when the user is just scrolling down to view more data in the grid.  

To demonstrate the problem, open a copy of the virtualization grid demo, for example here:


Open the Developer Tools and just observe which network requests are sent to the server. Just scroll down in any way and observe that very often the exact same request is made. A request for the same data has the same Top and Skip values in the parameters sent the server. You can see the servers reply is exactly the same JSON data multiple times after each other.

Solving this performance problem almost completely would seemingly be to in a variable just keep track of the "Latest request" sent, since the problem happens mostly just with normal scrolling in one direction with request sent after each other. So one would need to keep track of that a call for Top 100, Skip 200 has been made, and if the program wants to request the exact same data again, just wait for a reply for the first request, instead of sending a new one. (If needed, send a new request only after a specific timeout for a reply for the first one).

A more thorough solution would be to have a data structure to keep track of the Top and Skip tuples for all the calls to the server that has not yet have had a reply from the server, and not repeat those exact same calls again if still waiting for a reply for the first request.

Last Updated: 21 Mar 2019 16:28 by Dimitris I.
Created by: Dimitris I.
Comments: 6
Category: Kendo UI for jQuery
Type: Bug Report

He have created this dojo to illustrate our point.


We would like to be able to be able to clone options from the top options and subsequently to be able to edit any cloned (child) option. 

We are unable to figure out a way so that the child/cloned dropdowns can change state.

Is it a bug or a feature? How can we achieve our aim?

Thank you so much,


Last Updated: 29 Mar 2019 07:07 by ADMIN

Bug report

When the filtering mode of the grid is set to "row" and the filter is programmatically cleared, the "Clear filter" button does not hide.

Reproduction of the problem

Set filterable: {mode: "row"}.
Filter for instance "Is null" or "Is not null".
Clear the filter - $("#grid").getKendoGrid().dataSource.filter({});
The "Clear filter" button is not hidden
sample Dojo:


If there is text in the filter's input, the button is hidden.

Expected/desired behavior

Hide the "Clear filter" button, irrespectively whether the filter has been cleared programmatically or via the UI.


Kendo UI version: 2019.1.220
jQuery version: 1.12.4
Browser: [all]

Last Updated: 16 Apr 2019 09:55 by ADMIN
Created by: Reqs
Comments: 0
Category: Kendo UI for jQuery
Type: Bug Report

Video: https://www.youtube.com/watch?v=8pnFjgzdaJ8&feature=youtu.be

1. Navigate to: https://dojo.telerik.com/@milena/uZaGuZol (open the dojo sample in edit mode, but not in FullScreen)

2. Scroll Grid to the last item.

3. Open for editing ProductName cell.

4. Open for editing Discontinued cell.

Result: 'Discontinued' cell of the second item will be opened for editing.

Expected: 'Discontinued' cell of the last item should be opened for editing.

Pending Review
Last Updated: 23 Apr 2019 08:00 by ADMIN
Created by: Albert
Comments: 2
Category: Kendo UI for jQuery
Type: Bug Report



open new window using the button, and close all window one by one, then see that k-overlay is still stay in page

Last Updated: 20 Aug 2020 08:56 by ADMIN

Bug report

When a culture that uses a "comma" as a decimal separator is applied to the Kendo UI NumericTextBox, the value of the aria-valuenow attribute uses the value without transforming the "," separator into a "." separator.

Reproduction of the problem

Set a culture that utilizes the comma as a decimal separator. Notice the aria-valuenow attribute's value:



* **Kendo UI version:** 2020.2.617
* **jQuery version:** 1.12.4
* **Browser:** [all] 

Pending Review
Last Updated: 16 Aug 2019 14:49 by ADMIN

Reproduction steps:

1. Open column menu

2. Using arrow keys, go to Filter menu item.

3. Hit right arrow to open Filter submenu

4. Tab through filter submenu

5. Hit escape.

Expected behaviour: Filter submenu closes and focus returns to the parent column menu

Actual behaviour: Both filter and column menu are closed.

Snippet: http://dojo.telerik.com/@gearoidj/iqiwUCEp


This is an issue for accessibility users - there doesn't seem to be a way to return to the parent filter menu using the keyboard without closing all menus and reopening them.

There is one way for it to occur, and that is to use the mouse to place the focus on the Filter menu background - in this case hitting escape will close the Filter menu and focus will be returned to the parent column menu. However this is impractical for an accessibility user who is relying solely on keyboard navigation.


An example of where this (mostly) works is on the Columns submenu - the user can use the left arrow key or Escape to close the child menu or alternatively keep tabbing and they will eventually return to the parent menu (though if they do tab within the child menu, hitting Escape will close both the child and parent menus).

Last Updated: 04 Aug 2020 11:48 by ADMIN
Created by: Samir
Comments: 2
Category: Kendo UI for jQuery
Type: Bug Report

Bug report

The workbook exporting to Excel generates a corrupted file when the name of some of its sheets contains a "cell-related" value - for example, "A1", "G5", "F45", etc.

Reproduction of the problem

  1. Open this Dojo project and run it
  2. Save the exported Excel file and open it.

Current behavior

When the saved file is opened in Excel, a "corrupted file" warning appears on the screen.

Expected/desired behavior

There shouldn't be any warnings when opening a saved workbook


  • Kendo UI version: 2019.3.1023
  • jQuery version: x.y
  • Browser: [all]
Last Updated: 28 May 2020 12:34 by ADMIN


I prepared a demo https://dojo.telerik.com/EYeYUSUw/6

Also applies to the latest default sass theme but probably to many more.

As you can see, the master grid its 'content row' hover effect is being applied to even the header of the detail grid and there is no way to resolve that unwanted effect apart from adding more styling tedious rules. 

The resolution is so simple:

.k-grid tbody tr:hover, .k-grid tbody tr.k-state-hover {
    background-color: #e6e6ea;

Should be

.k-grid tbody > tr:hover, .k-grid tbody > tr.k-state-hover {
    background-color: #e6e6ea;


I did not search for the source files/lines what might need to change - easy to find in your current version.

There could be many more of these simple improvements which would save many hours on ours side!



Last Updated: 21 May 2020 11:40 by ADMIN

Step by step instructions on how to reproduce the problem:

  1. Create a kendo tab strip
  2. Using the append method, add a "tab1"- do not specify any content in this new tab
  3. Using the insertBefore method, add a "tab2", this time specify some content
  4. Attempt to navigate the tabs and note what is showing in the content of each tab

Code snippets:

            var tabStrip = $("#contentlessAppend").kendoTabStrip({}).data('kendoTabStrip');
              text: "noContentAppend",
              //content: "With content" //Uncomment this line for normal functionality
              text: "contentInsertBefore",
              encode: false,
              content: `<div id="WhereAmI">I am not where I should be</div>`
            }, tabStrip.tabGroup.children().eq(0) );

Screenshots of the problem:


Stack trace, if applicable: N/A

Project and its dependencies which illustrates the problem (stripped, in zip format):

(see attached)

Last Updated: 01 Apr 2020 09:51 by Jean Yves

Bug report

When there is a DOM element with "page-break" class inside an element that is about to be exported to PDF, this "page-break" results in a new page in the reported PDF file.

If we hide the parent element in which the element with a "page-break" class is nested and export the content to PDF, in the result file, the content of the hidden DIV is not displayed but there are blank pages for each "page-break" class that can be found in the hidden element.

Reproduction of the problem

  1. Open this Dojo and run it
  2. Press the "Hide the DIV element in red" button
  3. Press the "Export to PDF button" and open the exported file

Current behavior

There are two blank pages at the beginning of the exported document. Each of these pages is a result of the "page-break" CSS classes inside the "#test" element

Expected/desired behavior

The "page-break" class should not result in the exported file if it is nested in a hidden element. Here is a Dojo demonstrating the correct behavior: https://dojo.telerik.com/iZAXiZEz


  • Kendo UI version: 2020.1.219
  • jQuery version: x.y
  • Browser: [all]
Pending Review
Last Updated: 23 Nov 2018 15:54 by ADMIN

This is an error that took us an hour to figure out.

We are using the right-arrow icon as part of the content within a collapsible header to represent a state transition. (See image)

We found that the expand/collapse icon did not appear.


Further investigation reveals that if the header content contains a span with a class matching the regular expression k-i-arrow.* then the expand/collapse icon doesn't work. It could contain anything else, it was just that one class pattern that threw it.

See this example. https://dojo.telerik.com/EwAsaKAf/3

I also posted a forum message here: https://www.telerik.com/forums/expand-collapse-arrow-fails-to-appear-if-a-class-matching-a-certain-pattern-appears-anywhere-in-the-header   

This is clearly a bug, and one that I suspect can be fixed easily.

Last Updated: 28 Nov 2018 11:34 by ADMIN
<div class="filterField">
<label for="filterTags">Tags</label><br/>
<div class="filterFieldBody">
<input id="filterTags"/>


$( document ).ready( function ()

$( "#filterTags" ).kendoMultiSelect( {
placeholder: "Select Tag(s)",
autoClose: false,
dataTextField: "text",
dataValueField: "value",
autoBind: false,
dataSource: [
{ text: 'Summery Love Campaign', value: '1' },
{ text: 'Melbourne Cup', value: '2' },
{ text: '2018 Formals', value: '3' },
{ text: '2018 Schoolies Dance Club', value: '4' },
{ text: '2018 Schoolies Beach Fun', value: '5' },
{ text: 'Bridesmaids', value: '6' },
{ text: 'Wedding', value: '7' }
//value: [], without value set to an empty array kendo ui assumes value:[''] but with an array count of 0

// which causes all kinds of issues most especially when deleting
change: function ( e )
tagIds = this.value();
} );

} );
Last Updated: 21 Jan 2019 09:14 by ADMIN

Dojo example.

1. Resize the browser window so that its height is smaller than the DropDownTree's popup height.
2. Click the DropDownTree to open its popup.
3. The popup opens and then auto-closes

1 2 3 4