Last Updated: 26 Jul 2023 07:37 by ADMIN


Our team is using MobX-State-Tree (MST) and KendoReact TreeList control with virtual scrolling enabled. According to documentation MST model stores data as an observable array ( and

The MST model’s field ‘tree’ is not a regular array, but a LegacyObservableArray.

From UI standpoint: 

  • initially all tree nodes are collapsed

  • user clicks on i.e. 3rd tree node

  • selection is not displayed on any tree node (3rd node expected to be selected)

  • user expands 1st tree node - selection is set on the 3rd tree node

The following warning appears in the browser console. 

Warning: Failed prop type: Invalid prop `data` of type `object` supplied to `TreeList`, expected `array`.

    in TreeList (created by wrappedComponent)

    in wrappedComponent (created by wrappedComponent)

    in div (created by wrappedComponent)

    in div (created by wrappedComponent)

    in wrappedComponent

Model is defined as:

const TreeViewModel = types

    .model('TreeViewModel', {

        selectedItemUUID: types.maybe(types.string),

        tree: types.optional(types.array(TreeNodeModel), []),

        isLoaded: types.maybe(types.optional(types.boolean, false)),

        treeTypes: types.optional(types.array(TreeNodeTypeModel), []),


    .views((self) => ({

        get treeCollection(): any {      

            return self.tree;



Component is defined as:

        return (<>

            {!viewModel.isLoaded && loadingPanel}

            <div className='treeListContainer' ref={stageCanvasRef}>

                {treeListContainerHeight && <TreeList

                    style={{ maxHeight: `${treeListContainerHeight}px`, overflow: 'auto', }}











The following workaround allows converting an observable array to a regular array.

    .views((self) => ({

        get treeCollection(): any {      

            return JSON.parse(JSON.stringify(self.tree));    // or self.tree.slice()



This solution affects performance due to array copy. 

Besides this TreeList uses an array copy. User’s selection and expanding don’t trigger related changes in the initial observable array in the model.

Related event handlers (i.e. onSelectionChange, onExpandChange) should be extended to make appropriate changes in the MST model.

Can you please extend KendoReact controls to support observable arrays?

Is there a better solution?

Last Updated: 20 Apr 2023 07:16 by ADMIN
Created by: Aaron
Comments: 0
Category: Rating
Type: Bug Report
Details in forum post:
Last Updated: 25 Oct 2022 13:01 by ADMIN
Created by: Grant
Comments: 4
Category: KendoReact
Type: Bug Report

Hi Team, 

If you take a look at my demo, I have 2 scheduler events, and I've created a custom SchedulerItem that renders the background of one of them to be blue.

When dragging the items around, the dragItem mains the same color with a bit of opacity, cool.

When resizing, the orange (?) one works great, this is the default color theme. However when I resize the blue one, while resizing, the resizeItem is an opaque blue, but the SchedulerItem underneath reverts back to the original default color scheme thereby mixing the colors.

Please advise.


Last Updated: 18 Aug 2022 12:28 by ADMIN

Test Environment:

OS: Windows_11
Version: 21H2
OS Build: 22000.795

Browser: Version 103.0.1264.71 (Official Build) (64-bit)

Prerequisite steps:

1. Go to system settings.

2. Navigate to 'Accessibility' and activate it.

3. Navigate to 'Contrast theme' and activate it.

4. Select 'Desert/Aquatic' High Contrast theme in the combo box.


Repro Steps:

1. Open given URL in Edge.

2. Graph page will be open. 

3. Turn on High contrast theme. 

4. Verify that Graphs are not adapting high contrast Aquatic and Desert modes or not. 


Actual Behavior:

Graphs are not adapting high contrast Aquatic and Desert modes. They remain same as in normal mode.  


Expected Behavior:

 Graphs should adapt high contrast Aquatic and Desert modes as defined. All elements should adapt to respective modes properly. 

Last Updated: 07 Jan 2022 12:22 by ADMIN

Hi there, 
Im use chart component, and  sometimes the tooltip on grid disappear, i dont know why, and if i put the same code on the telerik this bug doesnt happen, here is an exemplo with the same data 

import * as React from 'react'
import * as ReactDOM from 'react-dom'

import {
} from '@progress/kendo-react-charts';

import 'hammerjs';

	const valueAxis = [
			name: "",
			format: "{0:n1}",
			font: "10px Roboto",

const seriesValues = [
			type: "bar",
			toolTipFormat: "{0:n2}",
			title: "Teste 1",
			spacing: 1,
      data: [27869.8616],
			type: "bar",
			toolTipFormat: "{0:n2}",
			title: "Teste 2",
			spacing: 1,
      data: [13277.95],
			type: "bar",
			toolTipFormat: "{0:n2}",
			title: "Teste 3",
			spacing: 1,
      data: [95164.9968],
			type: "bar",
			toolTipFormat: "{0:n2}",
			title: "Teste 4",
			spacing: 1,
      data: [115579.184],
			type: "bar",
			toolTipFormat: "{0:n2}",
			title: "Teste 4",
			spacing: 1,
      data: [null],
			type: "bar",
			toolTipFormat: "{0:n2}",
			title: "Teste 4",
			spacing: 1,
      data: [616.7145289747288],

const ChartContainer = () => (
    {, idx) => (
          visible: e.visible !== undefined ? e.visible : true,
          format: e.format,
          rotation: "auto",
          font: e.font,
      {, idx) => (
            font: '10px',
            format: "{0:n2}"


  <ChartContainer />,


I inspected the page and realized this, that div is the tooltip and thats working normally, k-animation-container-show class, top and left properties on style;

and this one, is the tooltip that doest appear in the screen, does not have all class and style, just doesnt show up, 

However, the component inside that div was rendered, as can you see

Im using this version



Last Updated: 15 Oct 2021 05:18 by ADMIN


  1. Create a DateTimePicker.
  2. Use its value prop to programmatically control the value the control uses.
  3. Add clickable Button (or other means) to programmatically set the value to an invalid date (i.e. something like new Date("invalid!").
  4. Click the Button.  The date displayed becomes "NaN/NaN/NaN 12:NaN PM".  I suppose this is reasonable.
  5. Now, click the calendar popup icon on the right-hand side of the component.


Displays a calendar popup, perhaps defaulting to the current date & time.


Throws an exception visible in the JavaScript console.  Replaces the UI with an error message.


import * as React from 'react';
import * as ReactDOM from 'react-dom';

import {
} from '@progress/kendo-react-dateinputs';
import { Button } from '@progress/kendo-react-buttons';

const App = () => {
  const [date, setDate] = React.useState(new Date());

  const handleChange = (event: DateTimePickerChangeEvent) => {

  const handleClick = () => {
    setDate(new Date('invaild!'));

  return (
      <div className="example-wrapper">
          (use Alt+<code>↓</code> to open the date-time selector, <code>←</code>{' '}
          and <code>→</code> to navigate, <code>↑</code> to increment and{' '}
          <code>↓</code> to decrement the value)
        <DateTimePicker onChange={handleChange} value={date} />
      <Button onClick={handleClick}>
        Click me, then the calendar, to break the DateTimePicker.

ReactDOM.render(<App />, document.querySelector('my-app'));
Important note: This POC code uses version 4.9.0 of kendo-react-buttons.  I do not know what that translates to in terms of the "version" dropdown.  I can't tell if "2021.1.119" is applicable here.
Last Updated: 26 Aug 2021 10:44 by ADMIN

Hi Team, 

I have found an issue in the Grid Component that I think needs some attention, see below.,

## Current behavior
My GridColumns are not styling correctly when i hide/show them based on an edit state (for example). Some that have no width restrictions will the shortened then not lengthed.


## Current Version

KendoReact 4.8.0


## Expected behavior
If I hide/show a GridColumn, its width should not affect other GridColumns, only the Grid overall.


## Minimal reproduction of the problem with instructions

1. View how age is the only column visible with a width attr
2. Click "Switch Mode" and notice how 'Id' is not added, but a width of 80 is now applied to the 'lastname' column, the same width as age
3. Click "Switch Mode" back to view, and see how id is removed and a width of 60 is applied to the 'firstname' column.


## Investigation:
Some investigation in the DOPM revealed that the issue is centred around the <colgroup> of the Grid's <table>:
- step 2 does the following to the <col>s in the <colgroup>
  - add a new col to the beginning with a width, for the Id column
  - add a new col to the end with a width, for the Age column
  - DOES NOT clear the width of the col group that used to be the age column

- step 3
 - Simply removes the last <col> in the group. Does not affect hte attributes of the remaining <col>s


I hope this was informative and can be resolved soon.

Kind Regards,

Last Updated: 06 Aug 2021 10:23 by ADMIN
  1. Open the using valid credentials.
  2. open any related article.
  3. Navigate to 'Reply' button and invoke it.
  4. Navigate to 'ordered list' button and invoke it.
  5. Navigate to the edit region and type some ordered list items.
  6. Now, Navigate to the ordered list items and listen to Narrator announcement.

Actual Result:

On navigating to ordered list items with arrow keys, Narrator is only announcing first letters of the text and while navigating with 'caps-arrow' keys, Narrator is only announcing position details of the list items.

Note: this issue is not observed with nvda

Nvda version: 2020.2


On navigating to ordered list items with 'arrow keys' or using 'caps-arrow' keys, Narrator should announce the whole text of the list item including position details.

User Impact 
Knowing how many items are in a list is extremely useful to assistive technology users as they can know if they should attempt to skip the list, navigate to the end, help them recall placement of certain items, or orient themselves within the list.  

Last Updated: 27 Apr 2021 10:44 by ADMIN
Created by: Aske Hippe
Comments: 1
Category: KendoReact
Type: Bug Report

The navigation sidebar smooth scroll animation doesn't work for the Calendar component.

Here is a codesandbox that showcases the issue:

Thanks in advance for fixing this :-)


Last Updated: 27 Apr 2021 10:42 by ADMIN
Created by: Aske Hippe
Comments: 1
Category: KendoReact
Type: Bug Report

Hi there!

I've written this component for a custom message input box for the Chat in Conversational UI for React:

import { ChatMessageBoxProps } from '@progress/kendo-react-conversational-ui'
import { FC } from 'react'

const CustomChatMessageBox: FC<ChatMessageBoxProps> = (props) => {
  return (
				className="h-full w-full text-base md:text-sm focus:outline-none"

export default CustomChatMessageBox

I'm supplying this component to the `messageBox` prop of the Chat component. However, sending the message doesn't work; neither by pressing enter or pressing the send button. If I replace the input with props.messageInput, it works.

Any help in fixing this will be greatly appreciated!

Thank in advance :-)

Last Updated: 27 Apr 2021 10:07 by ADMIN

The width of the Kendo React DatePicker can become small due to the container width.

In such case, consider the following use case

Users select the date part (year) and start incrementing it by the "up" key. The year date part is selected, but is partially visible,

and the users do not see the date part that they are currently modifying, while they can fully see the other date parts that are not currently in focus.


The DateInput needs a horizontal scrolling to ensure that a focused date part is fully visible to the users in case if the width of the component is narrow.


Please check the case here 

Last Updated: 27 Apr 2021 09:38 by ADMIN
Getting started page tuto - App.js should be App.jsx. When you use the latest version of VSCode - js deformates tags - in good old js, there are no tags. Just edit to jsx, and edit npm start command
Last Updated: 27 Apr 2021 07:42 by ADMIN
Created by: Andy
Comments: 1
Category: KendoReact
Type: Bug Report

DateTimePicker opens above or below the link to open it, however when it's in the middle of a page, it will choose to open below and sometimes require scrolling to see all the buttons.

Would be better, if it were to open offscreen, it should be "pinned" to the bottom edge.  Same for right/left/top borders of the screen.

Certain containers also make it impossible to scroll down to see the buttons, so that creates a real problem. The above proposal would fix this.



using fairly vanilla implementation of the component:

      defaultValue={new Date(ActivationDate.toString())}

Last Updated: 24 Feb 2021 12:13 by ADMIN

Defined a date rang. But it allows to enter a date larger than a max date of the range. Both via calendar and manually.

const minDate = new Date(1, 1, 1);
const maxDate = new Date(9999, 12, 31);

          return (
              <DatePicker value = {this.state.value}

Last Updated: 21 Jul 2020 10:24 by ADMIN
Created by: FIIG Securities
Comments: 3
Category: KendoReact
Type: Bug Report

There seems to be bug in the React Grid around date formatting inconsistencies:

Current behavior
When entering a date format of {0:dd/MM/yyyy} for a ColumnData prop, when in edit mode a calendar picker shows the date format as US date of MM/dd/yyyy.Expected behavior
The date should show as dd/MM/yyyy per the requested date format.Minimal reproduction of the problem with instructions
Create a Kendo grid with one column with following ColumnData:
const settlementDate: ColumnData = {
field: 'settlementDate',
title: 'Setlement Date',
format: '{0:dd/MM/yyyy}',
filterable: true,
filter: 'date',
editor: 'date'
Note that the date is displayed as MM/dd/yyyy
Change the format to "dd/MM/yyyy"
Note that when in view mode the date is displayed as "dd/MM/yyyy".
What is the motivation or use case for changing the behavior?
Currently I have to create a custom date cell for every instance of using a date field in my grid which is less than ideal.Environment
Package versions:
@progress/kendo-base-component-react-wrapper@2019.2.606 deduped
@progress/kendo-ui@2019.3.1113Browser:Chrome (desktop) version 78.0.3904.108
Platform: Windows

Other information:
It appears that there is an incompatibility as to what a text display field requires as opposed to what a date picker requires. For text display it requires a format of '{0:dd/MM/yyyy}' whereas the datepicker requires a format of "dd/MM/yyyy".

Last Updated: 03 Jul 2020 06:00 by ADMIN

I am trying to lock first column in Grid, when I used the instructions in Kendo React documentation I tried the same but as you see in screenshots it's not working.

Last Updated: 24 Dec 2019 08:07 by ADMIN

In the case of multiple columns headers, the column width of the KendoReact  TreeList  is invalid



const columns = [
   { field: 'name', title: 'Name', width: 300, expandable: true }
    { title: 'Employee Details', width: 600, children: [
        { field: 'position', title: 'Position', width: 500 },
        { field: 'fullTime', title: 'Full Time', width: 100 }
    ] }
Last Updated: 07 Aug 2019 06:27 by ADMIN

The tooltip display position of KendoReact Chart  is incorrect

See the code.thank you




Last Updated: 26 Jun 2019 14:05 by ADMIN
Created by: Nathaniel
Comments: 1
Category: KendoReact
Type: Bug Report

I am using the ComboBox component in IE11.  When the control has a value, the clear button covers the select arrow at the right of the control.  This occurs because IE11 does not allow nested calc() calls in the CSS width property, e.g. 

.k-dropdown-wrap .k-clear-value {
    right: calc(calc( 0.75rem + 17px) + 6.5px);

Removing the inner calc() works well enough:

.k-dropdown-wrap .k-clear-value {
    right: calc(( 0.75rem + 17px) + 6.5px);

Unfortunately, this rule seems to originate from a CSS function call to which I do not have access.  Is it possible to remove the inner calc()?

Last Updated: 26 Jun 2019 14:04 by ADMIN
Created by: Nathaniel
Comments: 6
Category: KendoReact
Type: Bug Report

When rendering an AutoComplete, I get the following warning:

Warning: Failed prop type: Invalid prop `children` supplied to `Popup`.
    in Popup (created by ListContainer)
    in ListContainer (created by AutoComplete)
    in span (created by AutoComplete)
    in AutoComplete

I have tried this in the simple case below:

        validationMessage="Location Required." />,
1 2