Hi Progress Telerik Team,

Our security team has reported a Content Security Policy issue related to inline scripts in Progress Telerik UI for ASP.NET AJAX. Could you please add nonce support for inline scripts so we can resolve this issue in a compliant way?

Please let us know if you need any additional details from our side.

Thank you,
Hira Kewlani

After upgrading to 2026.2.708, RadAsyncUpload file uploads fail with HTTP 403 Forbidden originating from the new CSRF validation (AsyncUploadHandler.ValidateCsrfToken). The handler returns an HTML error response.

The failure occurs only in our multi-host (load-balanced) environment. In multihost environment as well Issue is inconsistent. The exact same build works correctly on a single-node local/dev machine.

Refer support ticket raise for the Issue to get more detail.

RadAsyncUpload fails with HTTP 403 (ValidateCsrfToken) in multi-node/web-farm environment after upgrade to 2026.2.708 | View Ticket | Your Account

Currently the the ImageEditor (and the Editor) are looking for standard .ascx files with the names of its dialogs and it is not optimized for a scenario in which these dialogs are pre-compiled.

Subresource Integrity is a fairly new security scheme for protecting against malicious script obtained from third-party source (CDNs). It requires that the script tag include a hash of the script content so the browser can verify that it has not been altered.

Telerik controls generate a bunch of script tags for cloudfront.net. It would be swell if the script tags would include the extra attributes necessary to implement subresource integrity. Is this in the roadmap? 

Mozilla provides a security analysis tool which highlights this issue. Look at the results for telerik.com here -> https://observatory.mozilla.org/analyze/www.telerik.com. 

More info available on 
https://infosec.mozilla.org/guidelines/web_security#subresource-integrity
https://www.w3.org/TR/SRI/

Please create a method that will convert the old expressions to new format and make them re-usable again.

When I edit text in RadEditor with Track Changes enabled and insert a new line, the editor does not track the insertion of the new line

I know that this command is not supported actually, but has a possibility this feature is available in next versions? or a palliative code?

Hi Team,

I would like to request the following image file extensions to be displayable using the RadEditor's ImageManager/DocumentManager.  

• abci
• avif
• heif
• heic
• webp

Thank you!

There is significant latency when a user has many images in a list or dropdown list, particularly those with sub-choices that also have images.  Because of this, we tried implementing design-time templates to allow lazy loading of images for RadComboBox.  While implementing a solution is possible, it was much more complicated than expected.

We have previuisly raised a feature request for simular controls that was fixed (Thanks for that) but our topp prioority component is The combobox. see Allow lazy loading of images with design-time templates for ListBox and ComboBox

During the discussion a few questions was rasied from telerik:

Currently, the ComboBox has the Load on Demand functionality which focuses on loading items as needed, but it does not specifically address lazy loading of images inside the templates. Before proceeding further, I’d like to confirm your current setup to suggest the best approach:

• Are you using server-side or client-side data binding with RadComboBox?
• Are you using design-time templates or injecting templates dynamically?
• How are images currently loaded in your ComboBox items?
• Is your main concern the initial load time, scrolling performance, or something else?

Reasons (Hope it makes sense)

• Only server-side databinding (with both controls).

• We are using both ItemTemplate with custom images (where we then control lazy loading ourselves) and ImageUrl where we lose this possibility and have issues. We also dynamically load custom controls (ITemplate) in a few places.

 

There is significant latency when a user has many images in a list or dropdown list, particularly those with sub-choices that also have images.  Because of this, we tried implementing design-time templates to allow lazy loading of images for ListBox and ComboBox.  While implementing a solution is possible, it was much more complicated than expected.

One specific problem we encountered was that when using a template, the ListBox wraps its internal label in a span (which the ComboBox doesn't do).  This results in problems with data-binding (requiring an item-by-item solution) and requires specialized css to handle.  Even after the basic solution was working, sub-choices still had a problem accessing text and image data.  This could be solved with a custom frontend runtime template, but it was not an elegant solution.

Our feature request is for lazy loading to be an option for images for the ListBox and ComboBox.  This would significantly improve the user experience with long lists and drop-downs. 

Hi, I would like to request that you add the ability to show/hide a hidden password similar to this: https://www.telerik.com/support/kb/aspnet-ajax/textbox/details/showpassword-button-for-radtextbox-with-textmode-password

This feature should be built into the toolkit, and not require custom coding.

Right now the end user can resize the table cells only through the provided interface in the Table Wizard and Properties inspector module. It will be useful this to be enabled as resize handlers directly in the table as it is implemented in the Kendo Editor - https://demos.telerik.com/kendo-ui/editor/index.

I am currently using the Radeditor "Insert Table" function. I would like this to allow user to auto adjust columns and rows live just like the following demo. https://demos.telerik.com/aspnet-mvc/editor.  I have disable the table wizard and table properties, so user will not be able to mess with this extra stuff. In the Capture.PNG is what I currently have. I would like to have the Want.PNG picture. 

is it possible for the radnumerictextbox control to pop up with numeric keyboards on mobile devices yet?  I see old KB articles that said no, but they were pretty old.

When inserting video in Telerik Editor, radEditor by default inserts it using <embed>.
This element is not supported by Edge. Many modern browsers now support/recommend to use of the <video> tag.
So, that it will render video in most of Chromium browsers out there.

 

 

Please update the RadODataSource to support the newest version of OData. The syntax for filtering (among other things) has changed, so I am unable to implement this control with my chosen technology stack until it is updated. Thanks!

Discovered that the screen reader is not announcing the select list options. The previous ticket made these keyboard accessible and selectable.  Right now, the use of a screen reader only announces: 

With JAWS
Paragraph Style button menu
Font Name button menu
Real Font button menu
Zoom button menu

With NVDA
Paragraph Style sub menu
Font Name sub menu
Real Font sub menu
Zoom sub menu

 

Using Alt+down arrow to expand the select option menu, using the arrow keys to navigate down the menu nothing is announced although you can visually see the focus highlight in the menu.

This is the same for the two screen readers JAWS and NVDA. Same result when testing on Edge and Chrome browsers.

Other menu options or expandable sections are having a similar issue for:

Paste Options
Foreground Color
Background Color
Paint Stripper
Insert Symbol
Insert Table
Module Manager this one is empty when it expands

Thank you.

Hello Telerik Team,

I'm implementing HeaderContext filtering with checkbox lists on a RadGrid in a legacy ASP.NET WebForms application. 

Current Setup:
- FilterType="HeaderContext"
- FilterCheckListEnableLoadOnDemand="true"
- OnFilterCheckListItemsRequested event populates checkboxes from session data

Issue:
Users experience 500-2000ms delay when opening filter menus (AJAX callback to server). 
In our production environment with slow network and high concurrent users, this creates 
poor user experience.

Questions:
1. Is there a way to pre-populate checkbox lists during grid initialization 
   (avoiding AJAX callback)?
2. Can we use OnItemCreated to populate checkbox lists with 
   FilterCheckListEnableLoadOnDemand="false"? If so, what's the correct approach?
3. Is there a client-side caching mechanism for checkbox list items?
4. What's the recommended pattern for large datasets (1000+ rows) with multiple 
   filterable columns?

Environment:
- Telerik.Web.UI version: v4.0.30319
- .NET Framework: 4.8
- Browser: Chrome, IE11
- Grid has ~10 columns with 5 using checkbox filters

Any guidance on performance optimization would be greatly appreciated!

Thank you,
Anurag pandey

Please implement WAI-ARIA support in RadSearchBox with and without a Search Context.

It needs the same type of logic added as the AutoComplete and ComboBox control so that JAWS can speak and navigate the list items properly.
It looks like there was a little started because it renders an ARIA live region for status, but never writes to it from what I can tell.

I know this document lists the current controls that support ARIA - http://docs.telerik.com/devtools/aspnet-ajax/controls/wai-aria-support-and-screen-readers

Thanks,
Mike