A property to handle that would be very convenient. This way developers could be able to restrict the number of rows that the user can type. Something like MaxRowNumber.

Additionally, a property MaxColumnNumber would be also useful to restrict the length of each row. 

Context / scenario

We run a large ASP.NET AJAX application with a fully custom, self-maintained CSS theme — we do not use any of Telerik's built-in skins. For this kind of setup we need complete control over every stylesheet that gets loaded into the page, both for consistency of our design system and to avoid unexpected CSS side effects or class-name collisions with resources we don't manage.

Issue

We found that fonticons.css is automatically and unconditionally injected by the Lightweight rendering path used by the controls (e.g. RadButton, RadTextBox, and other controls using the Lightweight render mode). This injection happens regardless of the EnableEmbeddedSkins and EnableEmbeddedBaseStylesheet settings, which normally let developers opt out of Telerik's embedded/base CSS resources. In other words, even with both of those settings disabled and no skin applied, fonticons.css is still loaded — there is currently no supported way to prevent it.

We raised this with Telerik support and it was confirmed internally: the fonticons.css injection is currently hard-wired into the Lightweight rendering path and is not gated by any existing configuration option.

Why this matters

• It breaks the expectation that EnableEmbeddedSkins / EnableEmbeddedBaseStylesheet = "nothing gets injected automatically" for teams running a fully custom theme.
• It adds an extra, unaccounted-for HTTP resource / set of CSS rules (font-face declarations and generic icon base classes) that our theme did not ask for and cannot easily audit or version alongside the rest of our stylesheet.
• Teams with strict content-security / asset-inventory requirements (e.g. wanting every loaded CSS file to be explicitly declared and controlled) currently have no clean way to achieve that with Telerik controls in Lightweight mode.
• The only current workaround (intercepting or modifying Telerik's internal resource registration) is explicitly discouraged by Telerik support itself, since that internal logic can change between versions and is not a supported extension point.

Feature request

Introduce a supported opt-out for the automatic fonticons.css injection in the Lightweight rendering path — for example, a new setting such as EnableFontIcons (page/control or global web.config level, consistent with how EnableEmbeddedSkins / EnableEmbeddedBaseStylesheet are already exposed) that lets developers explicitly disable this injection when they provide their own icon/font handling.

We understand from Telerik support that this is not a small, isolated change — it requires auditing and refactoring how style resources are declared and loaded across the whole control set (including some legacy resource-registration code) before a dedicated opt-out setting can be safely introduced, and that this carries a real risk of regressions if rushed. We're not expecting a quick fix; we're submitting this as a tracked feature request, as recommended by Telerik support, so it can be prioritized and voted on by other customers with the same fully-custom-theme use case.

Suggested acceptance criteria

• A documented way (config setting and/or API) to disable automatic fonticons.css injection specifically in Lightweight rendering mode.
• Behavior consistent with EnableEmbeddedSkins / EnableEmbeddedBaseStylesheet: when disabled, no font-icon CSS is emitted by the framework, leaving the developer fully responsible for providing equivalent styles if needed.
• No behavior change for existing applications that don't set the new opt-out (backward compatible by default).

RadPivotGrid persisted states do not restore saved filter values or apply the filters to the dataset.

The issue is reproducible on the Telerik demo site and also affects states newly saved with the affected versions. No runtime errors are observed.

The behavior worked in 2026.2.519.

Expected: Loading a persisted state restores the saved filters and applies them to the PivotGrid.

Actual: The state loads, but the saved filters are not restored or applied.

This appears to be a regression related to recent changes to the persisted state storage/restoration mechanism.

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

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.

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.

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. 

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.