After upgrade from
<package id="Telerik.Licensing" version="1.6.16" targetFramework="net472" />
<package id="Telerik.UI.for.AspNet.Ajax.Net462" version="2025.3.825" targetFramework="net472" />
to
<package id="Telerik.Licensing" version="1.6.40" targetFramework="net472" />
<package id="Telerik.UI.for.AspNet.Ajax.Net462" version="2026.1.225" targetFramework="net472" />
we started experiencing the following error:
1. Add editor with ToolbarMode="RibbonBarShowOnFocus", no code-behind is required
<telerik:RadEditor ID="Editor" runat="server" Width="100%"
ToolbarMode="RibbonBarShowOnFocus">
</telerik:RadEditor>2. Open page, editor is empty and "Design" tab is active
3. Click on "Html" tab. Important: don't click on the editor content area while "Design" tab is active!
4. Paste some html, e.g.
<p>Your third Quarter Dining Rewards are Ready!</p>
5. Click to "Design" tab. Content is not rendered, editor is broken.
6. Find error in console
ScriptResource.axd?d=SIX1nT3k5ctYiH_Z5iBDXSZnshOXvXkzvSku5HLBqZlwfCmxfuwQE-bsvfCtuJcU8Kf5mMmqIz4_-haUfplj_Y2fBjNYHTB6sDwvO7dqA9dlR0fcUTx4578VpqHDjGrfk4WQ4Qs5nyG4zIAFDPwYjQ2&t=7fbf35ab:1 Uncaught TypeError: Cannot read properties of null (reading 'commonAncestorContainer')
at Object.getState (ScriptResource.axd?d=SIX1nT3k5ctYiH_Z5iBDXSZnshOXvXkzvSku5HLBqZlwfCmxfuwQE-bsvfCtuJcU8Kf5mMmqIz4_-haUfplj_Y2fBjNYHTB6sDwvO7dqA9dlR0fcUTx4578VpqHDjGrfk4WQ4Qs5nyG4zIAFDPwYjQ2&t=7fbf35ab:1:143451)
at Object.getToolState (ScriptResource.axd?d=SIX1nT3k5ctYiH_Z5iBDXSZnshOXvXkzvSku5HLBqZlwfCmxfuwQE-bsvfCtuJcU8Kf5mMmqIz4_-haUfplj_Y2fBjNYHTB6sDwvO7dqA9dlR0fcUTx4578VpqHDjGrfk4WQ4Qs5nyG4zIAFDPwYjQ2&t=7fbf35ab:2:7097)
at Object.setRibbonBarToolState (ScriptResource.axd?d=SIX1nT3k5ctYiH_Z5iBDXSZnshOXvXkzvSku5HLBqZlwfCmxfuwQE-bsvfCtuJcU8Kf5mMmqIz4_-haUfplj_Y2fBjNYHTB6sDwvO7dqA9dlR0fcUTx4578VpqHDjGrfk4WQ4Qs5nyG4zIAFDPwYjQ2&t=7fbf35ab:3:124809)
at Object._onEditorSelectionChange (ScriptResource.axd?d=SIX1nT3k5ctYiH_Z5iBDXSZnshOXvXkzvSku5HLBqZlwfCmxfuwQE-bsvfCtuJcU8Kf5mMmqIz4_-haUfplj_Y2fBjNYHTB6sDwvO7dqA9dlR0fcUTx4578VpqHDjGrfk4WQ4Qs5nyG4zIAFDPwYjQ2&t=7fbf35ab:3:124488)
at Array.<anonymous> (MsAjaxJs?v=D6VN0fHlwFSIWjbVzi6mZyE9Ls-4LNrSSYVGRU46XF81:1:2148)
at MsAjaxJs?v=D6VN0fHlwFSIWjbVzi6mZyE9Ls-4LNrSSYVGRU46XF81:1:50368
at Object.raiseEvent (ScriptResource.axd?d=TDVjdgRbdvNAY3tnbizUcIjfDUXiq5ixpnBN0VcDALLSiZ3CMr6-87hfvIaN_0cz2j3vISyRnNQUUXuS5a7lBoLr1EhUzo3XC7p-5gq6HdUFDfDXoZF6FnTKoxdUmGE70&t=7fbf35ab:3:34795)
at Function.callBaseMethod (MsAjaxJs?v=D6VN0fHlwFSIWjbVzi6mZyE9Ls-4LNrSSYVGRU46XF81:1:8931)
at Object.raiseEvent (ScriptResource.axd?d=SIX1nT3k5ctYiH_Z5iBDXSZnshOXvXkzvSku5HLBqZlwfCmxfuwQE-bsvfCtuJcU8Kf5mMmqIz4_-haUfplj_Y2fBjNYHTB6sDwvO7dqA9dlR0fcUTx4578VpqHDjGrfk4WQ4Qs5nyG4zIAFDPwYjQ2&t=7fbf35ab:1:326487)
at Object.set_html (ScriptResource.axd?d=SIX1nT3k5ctYiH_Z5iBDXSZnshOXvXkzvSku5HLBqZlwfCmxfuwQE-bsvfCtuJcU8Kf5mMmqIz4_-haUfplj_Y2fBjNYHTB6sDwvO7dqA9dlR0fcUTx4578VpqHDjGrfk4WQ4Qs5nyG4zIAFDPwYjQ2&t=7fbf35ab:2:26992)
This is a production issue so any quick fixes/workarounds will be greatly appreciated.
The RadEditor Add Link dialog uses HTML tables for layout, but the tables are exposed with data-table semantics.
The dialog contains:
Because these tables are used to arrange form fields and buttons rather than display tabular data, screen readers and automated accessibility tools may interpret them as data tables. The hidden headers are removed from the accessibility tree and do not provide useful table semantics. The nested table may also result in redundant or confusing table announcements.
This causes WCAG 2.1 accessibility findings related to table semantics, including F49 and F91 under Section 508.