Bug report

When a decimal number has 8 digits after the decimal separator and '#' is used for formatting the precision is lost and the number is rounded.

Reproduction of the problem

1. Open the Dojo example and check the result in the console

Current behavior

kendo.toString(0.00000015,"###.########" returns 0.0000002

Expected/desired behavior

The number should not be rounded and the precision should not be lost. The results should be the same with kendo.toString(0.00000015,"n8") and kendo.toString(0.00000015,"0.00000000")

Environment

• Kendo UI version: 2022.3.1109
• Browser: [all ]

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:

https://dojo.telerik.com/rsdigZKk/4

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.

Hi Team,

I have getting warning message when open down loaded excel file . This warning is coming if we apply conditional formatting in kendo spreadsheet .Please 

check the URL

https://dojo.telerik.com/

Dear Concerned,

1. Open https://demos.telerik.com/kendo-ui/spreadsheet/index

2. Select column B and drag mouse towards C, both columns will be selected which is correct behavior

3. Now just scroll down 2-3 rows using vertical scroll bar

4. Repeat step 2, this time it does not select B &  C, instead it selects B,C,D,E.

5. Seems a bug, not an expected behavior.

Observation that might help you in fixing it:

1. if you move scroll bar in such a way so that no merged cell is visible it works well, e.g. scroll down till 20th row becomes first visible row on screen and now repeat step 2, it will work

2. if scroll position is on top then behavior is correct as well

3. Same issue exists in case of multiple row selection with merged column and scroll position.

The grid dataBinding event exposes useful information like the action, based on which I can implement my logic.

The treeList equivalent only has the sender, making it virtually useless.

When a kendoContextMenu is applied to a combobox (html tag select) you are not able to show the select options by tapping it. The behaviour is on mobile browser only (tested iPad and Google Chrome developer tools with device toolbar enabled).

I reproduced the issue in telerik dojo, here is the code.

<!DOCTYPE html>
<html>
<head>
    <base href="https://demos.telerik.com/kendo-ui/menu/context-menu">
    <style>html { font-size: 14px; font-family: Arial, Helvetica, sans-serif; }</style>
    <title></title>
    <link rel="stylesheet" href="https://kendo.cdn.telerik.com/2021.1.330/styles/kendo.common-bootstrap.min.css" />
    <link rel="stylesheet" href="https://kendo.cdn.telerik.com/2021.1.330/styles/kendo.bootstrap.min.css" />
    <link rel="stylesheet" href="https://kendo.cdn.telerik.com/2021.1.330/styles/kendo.bootstrap.mobile.min.css" />

    <script src="https://kendo.cdn.telerik.com/2021.1.330/js/jquery.min.js"></script>
    
    
    <script src="https://kendo.cdn.telerik.com/2021.1.330/js/kendo.all.min.js"></script>
    
    

</head>
<body>
    <div id="example">
      <select>
        <option>Opzione 1</option>
        <option>Opzione 2</option>
        <option>Opzione 3</option>
      </select>
      
    <ul id="menu">
        <li>
            <img src="../content/web/toolbar/reply.png" /> Reply
        </li>
    </ul>
      
</div>
<script>
    $(document).ready(function() {
        setTimeout(function () {
            var initMenu = function () {
                menu = $("#menu").kendoContextMenu({
                    target: "select",
                    select: function(e) {
                        // Do something on select
                    }
                });
            };

            initMenu();
        }, 0);
    });
</script>

</body>
</html>

Bug report

When sorting is enabled for a virtualized Grid, in some cases, after scrolling to the bottom, the Grid does not show enough items to fill the tnire table.

Reproduction of the problem

1. Open the Dojo - https://dojo.telerik.com/XZAkgwxd
2. Scroll to the bottom and sort the table, for example, by ID

Current behavior

The Grid shows only the last page of items, while there are enough items to fill up the entire table

Expected/desired behavior

Enough items to fill the Grid height should be displayed. There should be no blank space without records.

Environment

• Kendo UI version: 2025.4.1111
• Browser: [all]

Bug report

In an Editor that has a visible scrollbar, the selection event fires if you click on the scrollbar.

Reproduction of the problem

1. Open the Editor events demo - https://demos.telerik.com/kendo-ui/editor/events
2. Type some content until the scrollbar appears
3. Click on the scrollbar

Current behavior

The selection event triggers when you click the scrollbar

Expected/desired behavior

The selection event shouldn't trigger when you click the scrollbar

Environment

• Kendo UI version: 2023.2.718
• Browser: [all]

Bug report

When virtualization is enabled in the MultiColumnComboBox and the user scrolls down in the popup to load new items sometimes an item that is not actually hovered is highlighted as hovered (the 'k-hover' class is applied).

Reproduction of the problem

1. Open the Dojo
2. Scroll down to load new items. Note, that the behavior is not consistent and is not reproducible every time.

Current behavior

Sometimes random item that is not hovered has the 'k-hover' class.
screencast - https://www.screencast.com/t/KXhG7SBkE6

Expected/desired behavior

Items that are not hovered should not have the k-hover class and should not be highlighted as hovered.

Environment

• Kendo UI version: 2022.2.802
• Browser: [all ]

Bug report

Data validation should not require DATEVALUE("") in Start and End inputs when `Date` is selected

Reproduction of the problem

https://demos.telerik.com/kendo-ui/spreadsheet/index

1. Select an empty cell
2. Click Data validation
3. Set Start: DATEVALUE("1/1/2024") and End: DATEVALUE("2/2/2025")
4. Automatic Hint message looks like: between DATEVALUE("1/1/2024") and End: DATEVALUE("2/2/2025")

Expected
Generated hint message shall not contain DATEVALUE("")


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

Reproduction of the problem

1. Run this sample
2. Select first row
3. Delete the row
4. Select range A1:C3
5. Apply borders
6. Select row 3
7. Delete the row

Current behavior

Top border of cell B1 disappears

Expected/desired behavior

Borders are persisted

TicketID:

1708030

Environment

* **Kendo UI version:** 2025.4.1217

Test Environment:

Describe the bug
When there is an event that lasts multiple days, but is not an all-day event the title and the up arrow overlap, thus it makes the reading of the title harder.

To reproduce
Open the Dojo - https://dojo.telerik.com/@NeliK/IruYeGEc

Expected behavior
The arrow and the title should be rendered with some margin

Screenshots

Workaround

 .k-event-template{
      margin-top: 8px !important;
    }

Affected package (please remove the unneeded items)

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

Affected suites (please remove the unneeded items)

• Kendo UI for jQuery
• Kendo UI for Angular
• Kendo UI for React
• Kendo UI for Vue

Affected browsers (please remove the unneeded items)

• All

Bug report

Reproduction of the problem

1. Run this dojo
2. Try to select a file by clicking on its icon

Current behavior

The select event is not fired.

If clicked next to the icon the select works as expected.

Expected/desired behavior

The select event should be fired consistently

TicketID:

1719355

Environment

• Kendo/Telerik version: 2026.3.811

Hi support

I think I've found a bug in kendo ui 2026.3.811 DropDownButton. Whenever you call setOptions on an existing button (created with with showArrowButton = true), another arrow button is added. You can easily reproduce the issue with your jquery DropDownButton Appearance demo. First set 'Show Arrow Button' to true. Then change any other option.

Kind regards

Iggy

Bug report

Reproduction of the problem

When the Editor is rendered in a long page with a scroller and the user paste a content replacing the entire content, the entire page scrolls, not only the Editor content.

1. Open the Dojo - https://dojo.telerik.com/wKDfkpEW
2. Copy long content for example from above the Editor
3. Mark the entire content in the Editor and paste the previously copied content

Current behavior

The entire page scrolls and in some cases the Editor is not visible.

screencast - https://go.screenpal.com/watch/cOQTlxnxqVk

Expected/desired behavior

Pasting in the Editor should not affect the page scroller.

Environment

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

The Kendo Chart widget's documentation describes the setting seriesDefault.focusHighlight. However, in the typescript typings it is called focusHighLight (with a capital L).

The documentation matches the source code, but the typings do not.

Hi Team,

I would like to request a way to define the Legend Item's height.  This specific request is to allow the item to change size dynamically when the size of a container(such as a TileLayout, Window, etc..) shifts. 

Thank you! 

Configure open/close animations (effects and duration) for the Kendo jQuery Drawer, similar to ComboBox animation settings.

$("#combobox").kendoComboBox({
  animation: {
   close: {
     effects: "fadeOut zoom:out",
     duration: 300
   },
   open: {
     effects: "fadeIn zoom:in",
     duration: 300
   }
  }
});