After updating to the new version, our RadListBoxes are behaving strangely. This problem is especially apparent when using a RadListBox with checkboxes that need to scroll.

When the RadListBox has enough elements and a restricted height, it lets you scroll through the items. If you check an item's checkbox, the list box appears to select the first item you can see. At that point, the item that appeared selected becomes marked or something, and you will not be able to check or select any other item in the RadListBox unless that item is visible. It also snaps the scroll position of the RadListBox back to the marked row.

We have an old local install of our project running the 2025.3.825 version, and the RadListBoxs work just fine. This issue was likely caused by a change somewhere between the 2025.3.825 and 2025.4.1321 versions.

Steps to recreate:

1. Check an item's checkbox

2. Scroll the items until you cannot see the one you checked.

3. Try to check another item's checkbox.

The RadListBox component is having multiple Accessibility issues, including focus indicator and missing WAI-ARIA attributes.

In our application we use ListBox with property EnableMarkMatches set. When we enter a search criteria with the keyboard you see in the selected rows the search criteria Bold. (See attached screenshot)

When u click with the mouse on this bold search criteria you get an error message in the console of the browser:

 

RadListBoxScripts.js:1223 Uncaught TypeError: Cannot read properties of null (reading 'get_enabled')

    at c.RadListBox._onClick (RadListBoxScripts.js:1223:6)

    at HTMLLIElement.<anonymous> (RadListBoxScripts.js:476:4)

    at HTMLDivElement.dispatch (jQuery.js:3:12445)

    at r.handle (jQuery.js:3:9174)

 

This issue is reproducible at

https://demos.telerik.com/aspnet-ajax/listbox/examples/functionality/keyboardsupport/defaultcs.aspx?

We are using List box item scroll into view to scroll to the item selected in the list box. However, the scroll is not working in the Chrome browser in a UHD touch screen laptop device.

The problem happens when you select an item and then press the down arrow button to move it. The item does not move. If you then press the down arrow button a second time, it does move.

The control should provide support for the JAWS screen readers, which will enable it for use by visually impaired users.

More details are available in the following forum thread - https://www.telerik.com/forums/how-is-listbox-usable-for-screen-readers

A workaround is to disable the embedded jQuery and use an older version (for example, 1.11.1 which is the previous version the suite used): https://docs.telerik.com/devtools/aspnet-ajax/controls/scriptmanager/disabling-the-embedded-jquery

Repro steps:

1. put a listbox on the page
2. configure it so it does postbacks (e.g., on selection changed, or any other feature)
3. ivnoke said postback (e.g., select an item)

Expected: the action is carried off

Actual: Firefox throws TypeError: access to strict mode caller function is censored

Sample markup

        <telerik:RadListBox runat="server" ID="rlb1" OnSelectedIndexChanged="rlb1_SelectedIndexChanged" AutoPostBack="true">
            <Items>
                <telerik:RadListBoxItem Text="first" Selected="true" />
                <telerik:RadListBoxItem Text="second" />
            </Items>
        </telerik:RadListBox>