kendoPanelBar is not a function error in Web Report Designer in Blazor

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Report Designer - Web Report Viewer - Blazor
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Lasitha asked on 10 Mar 2023, 08:14 AM

I have implemented web report designer in Blazor Hybrid and .Netcore server application separately.  But it gives an error like mentioned below.

Uncaught TypeError: this.$toolsWrapper.kendoPanelBar is not a function
    at d.init ((index):9:818087)
    at new d ((index):9:817562)
    at o.init ((index):9:1199454)
    at new o ((index):9:1199060)
    at m.init ((index):9:488638)
    at new m ((index):9:487953)
    at new K ((index):9:875474)
    at y.init ((index):9:478896)
    at (index):9:477756
    at r.onload ((index):9:19389)

But i have implanted the libraries inside the index.html file like this.


    <!--Telerik Report Designer-->

    <script src=""></script>
    <script src=""></script>



    <!--for telerik report designer-->
    <script src="_framework/blazor.webview.js" autostart="false"></script>
    <script src="_content/telerik.webreportdesigner.blazor/telerikWebReportDesignerInterop.js" defer></script>
    <script src="https://localhost:7036/api/reportdesigner/designerresources/js/webReportDesigner/"></script>
    <script src="https://localhost:7036/api/reportdesigner/resources/js/telerikReportViewer"></script>  



this is the razor file

@using Telerik.WebReportDesigner.Blazor

<h1>Testing Web Designer</h1>

    #wrd1 {
        position: relative;
        width: 100%;
        height: 1880px;
        padding-right: 50px;

<link rel="stylesheet" href="" />

<WebReportDesigner DesignerId="wrd1"
                   ToolboxArea="new ToolboxAreaOptions(){ Layout = ToolboxAreaLayout.List}"
                   PropertiesArea="new PropertiesAreaOptions(){Layout = PropertiesAreaLayout.Categorized}" />

what can be the reason for this issue?

I think  <script src=""></script> library causing this issue. 

Also after adding this library head Telerik report viewer components are not working too. it's error like this.

       Uncaught (in promise) TypeError: e.children(...).kendoPanelBar is not a function
    at d (telerikReportViewer:9:112655)
    at new r (telerikReportViewer:9:112606)
    at HTMLDivElement.<anonymous> (telerikReportViewer:9:115742)
    at Object.each (telerikReportViewer:9:4145)
    at I.fn.<computed> [as telerik_ReportViewer_SideMenu] (telerikReportViewer:9:115687)
    at HTMLDivElement.<anonymous> (telerikReportViewer:9:116170)
    at Object.each (telerikReportViewer:9:4145)
    at Object.bind (telerikReportViewer:9:116082)
    at init (telerikReportViewer:9:143996)
    at start (telerikReportViewer:9:147870)
d @ telerikReportViewer:9
r @ telerikReportViewer:9
(anonymous) @ telerikReportViewer:9
each @ telerikReportViewer:9
I.fn.<computed> @ telerikReportViewer:9
(anonymous) @ telerikReportViewer:9
each @ telerikReportViewer:9
bind @ telerikReportViewer:9
init @ telerikReportViewer:9
start @ telerikReportViewer:9
Promise.then (async)
(anonymous) @ telerikReportViewer:9
Promise.then (async)
(anonymous) @ telerikReportViewer:9
Promise.then (async)
main @ telerikReportViewer:9
ReportViewer @ telerikReportViewer:9
(anonymous) @ telerikReportViewer:9
each @ telerikReportViewer:9
jQuery.fn.<computed> @ telerikReportViewer:9
createReportViewerWidget @ interop.js:8
(anonymous) @ blazor.webview.js:1
beginInvokeJSFromDotNet @ blazor.webview.js:1
(anonymous) @ blazor.webview.js:1
(anonymous) @ VM8:7
(anonymous) @ VM7:1


Is there any solution for this?


1 Answer, 1 is accepted

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Telerik team
answered on 14 Mar 2023, 11:32 AM

Hello Lasitha,

Indeed, the problem may be related to the Kendo version. Note that the one that you use, 2022.3.913 should work as expected with Telerik Reporting R3 2022 SP1 ( or later.

With Telerik Kendo UI (2022.1.301 or later) you may use Reporting R2 2022 ( - R3 2022 (

For Reporting R1 2022 SP1 ( you need Kendo UI (2022.1.119).

For previous Reporting versions, R1 2022 ( and before, you may use Telerik Kendo UI (2020.3.1118) or newer, but older than the above versions. The reason for this is breaking changes in Kendo with the above releases.

In brief, make sure you use Kendo 2022.3.913 with Telerik Reporting R3 2022 SP1 ( or R1 2023 ( Unfortunately, I cannot see which is the Reporting version that you use.

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