ASP.NET Web Forms report viewer sends a request to https://kendo.cdn.telerik.com/themes/10.2.0/default/default-ocean-blue.css automatically

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Unplanned

Last Updated: 01 Oct 2025 17:07 by ADMIN

Teofil

Created on: 23 Sep 2025 07:55

Category: Reporting

Type: Bug Report

ASP.NET Web Forms report viewer sends a request to https://kendo.cdn.telerik.com/themes/10.2.0/default/default-ocean-blue.css automatically

I am using the ASP.NET Web Forms report viewer. I do not have a reference to the https://kendo.cdn.telerik.com/themes/10.2.0/default/default-ocean-blue.css stylesheet in my source code, but the viewer adds such automatically during initialization. This causes issues because my app runs offline and shouldn't have such dependencies. Also, I already have loaded a reference that is hosted locally in my app, so the CDN one is obsolete.

1 comment

ADMIN

Petar

Posted on: 01 Oct 2025 17:07

Hello,

I have privately discussed this issue with Teo, but I will also share our findings to ensure that anyone who comes across this bug report in the future is aware of the workaround.

Problem

The issue is that when the report viewer page does not include a script reference for the subset for Kendo UI for jQuery components (i.e., `telerikReportViewer-kendo`), the ASP.NET Web Forms report viewer sends a request for it automatically, as well as one for the https://kendo.cdn.telerik.com/themes/10.2.0/default/default-ocean-blue.css theme from the CDN (which is not available offline).

Workaround

The workaround is to add an explicit script reference for "api/reports/resources/js/telerikReportViewer-kendo" at the top of the HTML page for the viewer, preferably within the <head> tag, and load the Kendo UI theme from a local file instead of counting on the CDN reference.

Regards,
Petar
Progress Telerik

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