Last Updated: 24 Mar 2023 15:14 by ADMIN
Release R1 2023 SP1
In general, disabled Controls get grayed out and turn inaccessible. Disabling the ComboBox using the set_enabled(false) would prevent users to interact with the ComboBox, but will not have a "disabled" style applied.
Last Updated: 03 Feb 2023 08:37 by Tim

I recently upgraded from ASP.NET AJAX 2014 to 2022 and ran into an issue with a RadComboBox. It can be reproduced with this code:


     <telerik:RadScriptManager ID="scriptManager" runat="server" />
            <telerik:RadComboBox ID="rcb" runat="server" Label="Medication:" AutoPostBack="true"
                Width="250" OnSelectedIndexChanged="rcb_SelectedIndexChanged">
                    <telerik:RadComboBoxItem Text="-- select --" Value="" />
                    <telerik:RadComboBoxItem Text="Benztropine 0.5 mg " />
                    <telerik:RadComboBoxItem Text="Buspirone 10 MG" />
                    <telerik:RadComboBoxItem Text="Haloperidol 100mg/ml" />
                    <telerik:RadComboBoxItem Text="Metaprolol 25 mg" />
                    <telerik:RadComboBoxItem Text="Quetiapin/Seroquel 400 mg" />
                    <telerik:RadComboBoxItem Text="Trazadone 150 mg" />
                    <telerik:RadComboBoxItem Text="Vitamin D2 50,000 units" />
            <label>SelectedIndex</label> <asp:Label ID="Label1" runat="server" Text=""></asp:Label>


protected void rcb_SelectedIndexChanged(object sender, RadComboBoxSelectedIndexChangedEventArgs e)
    Label1.Text = rcb.SelectedIndex.ToString();
    rcb.SelectedIndex = 0;

When "Benztropine 0.5 mg " is selected, the SelectedIndex in the selected index changed method is incorrectly set to 0, instead of 1. Selecting any other item in the list results in the correct SelectedIndex. I spent a lot of time debugging the code until I noticed that "Benztropine 0.5 mg " has a space at the end.

I found two workarounds:

1. Trim the trailing space from text.

2. Add values for each item.

This was not an issue with the old 2014 version. Is this a bug or am I missing something?

Last Updated: 26 Oct 2022 14:33 by ADMIN
Release R3 2022 SP1

RadComboBox Bootstrap Lightweight skin is not loading in version 2022.3.913

Workarounds provided by Admin:

Option 1

Use RadStyleSheetManager to load the correct stylesheet from Telerik.Web.UI.Skins assembly, as per the instructions in Skin registration with RadStyleSheetManager:

<telerik:RadStyleSheetManager runat="server" ID="RadStyleSheetManager">
            <telerik:StyleSheetReference Name="Telerik.Web.UI.Skins.BootstrapLite.ComboBOx.Bootstrap.css" Assembly="Telerik.Web.UI.Skins" />

Option 2

Link the correct stylesheet manually on the page in one of the following ways:

Last Updated: 26 Aug 2022 11:21 by ADMIN
Created by: Peter Milchev
Comments: 0
Category: ComboBox
Type: Bug Report

Last Updated: 24 Jun 2022 12:56 by ADMIN
Last Updated: 22 Jun 2022 11:03 by ADMIN
Created by: Peter Milchev
Comments: 1
Category: ComboBox
Type: Bug Report

Last Updated: 20 Jun 2022 14:48 by ADMIN
Created by: Hristo Valyavicharski
Comments: 0
Category: ComboBox
Type: Bug Report

Last Updated: 08 Jun 2022 08:17 by ADMIN
Created by: Ivan Danchev
Comments: 0
Category: ComboBox
Type: Bug Report

Last Updated: 11 Feb 2022 14:19 by ADMIN
I have instances of using OnClientBlur on multiple RadComboBox controls, and if you tab quickly enough the event does not fire.  I've created an example which replicates what I see in the project I'm working on - two RadComboBoxes with the Blur event where I get the second to fire but not the first when tabbing from first to second to third (just another control w/o event).

This is causing issues where some validation is bypassed.


A couple observations:
- It will fire correctly if I wait long enough before tabbing out.
- If I pause on the second control after tabbing, then click somewhere, it sometimes then fires the Blur from the first control.
- I am using LoadOnDemand.  From my general observation it looks like it's potentially a race condition with the loading.

Last Updated: 14 Jan 2022 11:04 by ADMIN
Scheduled for R1 2022 SP1
"Loading..." text in Combobox with Virtual Scrolling is visible on first set of items loading.
It shows first time "Loading..." text. on scrolling it loads items from PageMethods/WebService but "Loading..." text it not visible i.e. because it is first <LI> item so it is not visible.

Instead of first <LI> item, it  should be at position where it always display while loading more items.

same issue is also in telerik demo website :
Last Updated: 16 Dec 2021 16:05 by ADMIN
Release R1 2022

<telerik:RadComboBox runat="server" ID="CB" AllowCustomText="true" HighlightTemplatedItems="true" EnableViewState="false" CheckBoxes="true" EnableLoadOnDemand="true" OnItemsRequested="CB_ItemsRequested" ></telerik:RadComboBox>

Specifically, note that CheckBoxes is true.

In some cases, the combo box's  item's text may have HTML tags in them, but we don't want that HTML to be interpreted, and we're happy that RadComboBox automatically encodes the Item's name.  For example, the Item's text might be <img src=xxx onerror=alert(0)> , and of course we don't want that javascript to run. 

However, we have found a case where the text is not properly escaped, in which case the javascript does run and the alert popup shows.  The error is in RadComboBox.CheckBoxes.js, in the _checkedItemsTextsFitInputWidth function.  That function is passed the comma separated string of all the selected item's text.  This function wants to measure the width of the string, and so it creates a div off-screen, and then pushes the checkedItemTexts string into the div.  If the checkedItemTexts string contains any HTML tags that contain javascript, then that javascript is executed, which can be a XSS attack.

Last Updated: 28 Oct 2021 09:06 by ADMIN
Created by: Tom
Comments: 1
Category: ComboBox
Type: Bug Report

At the first time requesting data, RadClientDataSource sends multiple requests to the server. All subsequent requests for Paging, Sorting work as expected.

Last Updated: 10 Aug 2021 15:19 by ADMIN
Created by: Paul Rogers
Comments: 1
Category: ComboBox
Type: Bug Report
We are running HTML validators as part of an effort to attain WCAG 2.0 A compliance.

Among the errors we are seeing is

The summary attribute is obsolete. Consider describing the structure of the table in a caption element or in a figure element containing the table; or, simplify the structure of the table so that no description is needed.

Here is a snippet of the failing HTML, apparently from the rendering of the RadSocialShare control:

	<div id="ctl00_TemplateBody_WebPartManager1_gwpciNewSocialShareCommon_ciNewSocialShareCommon_RadSocialShare1_compactPopup_C_comboBox" class="RadComboBox RadComboBox_Default" style="width:160px;">
<table summary="combobox" border="0" style="border-width:0;border-collapse:collapse;">

We are currently running version 2013.2.717.45 of the ASP .NET for AJAX controls, but we just tried 2013.3.1015.45 and it didn't fix things in this regard, either.

There is a similar discussion at , which recommends a jQuery fix.  This fix works in terms of removing the summary attribute from that table, but it does not result in clean HTML when the w3c validator is run against it, so we believe that is not an acceptable workaround.

In the discussion at , some mention is made of fixing the combo box for the 2012 Q3 release, but it doesn't look like that happened.
Last Updated: 09 Jun 2021 18:19 by ADMIN
Created by: Dave
Comments: 0
Category: ComboBox
Type: Bug Report

The OnClientTextChange event is triggered inconsistently in RadComboBox.

Typing custom text in the following RadComboBox and pressing enter does not fire the event:

        <script lang="javascript" type="text/javascript">
            function OnClientTextChange(sender, eventArgs) {
                alert("You typed " + sender.get_text());

                <telerik:RadComboBoxItem Text="item1" Value="item1" />
                <telerik:RadComboBoxItem Text="item12" Value="item12" />
                <telerik:RadComboBoxItem Text="aaaa" Value="aaa" />
                <telerik:RadComboBoxItem Text="bbbb" Value="bbb" />
                <telerik:RadComboBoxItem Text="AAAA1" Value="AAAA1" />
                <telerik:RadComboBoxItem Text="bbbb1" Value="bbb1" />
                <telerik:RadComboBoxItem Text="item11" Value="item11" />

Last Updated: 09 Jun 2021 18:08 by ADMIN

Example demo:

And here's what JAWS sees:

Note the extra unlabeled "Button" following every combo box. This is confusing to the reader. They have no way to know that it is associated with the preceding field.

Additionally, I've noted that when aria-support is turned on, this button becomes focusable. Tabindex="0" is added to the span inside the text box. We prefer the older functionality where the button was not a tab stop. Which is the same behavior you have when aria support is turned off. For reference, see your own aria demo:

Note that the tab key stops on the drop down arrow. (You can check the previously linked demo and see that the arrows in those boxes are not tab stops.)

If right-click the arrow and inspect, you'll find the following: 

<span id="ctl00_ContentPlaceholder1_RadComboBox2_Arrow" class="p-icon p-i-arrow-60-down" role="button" aria-controls="ctl00_ContentPlaceholder1_RadComboBox2_listbox" tabindex="0"></span>

Adding aria support should not change behavior, so we'd prefer the tab stop was removed.

In our own application, we have additional problems when the button is focused and activated with either the "space" or "enter" keys, it refocuses the field, but it does not actually open the drop down. I do not see that problem in your demo. However, if the arrow button was removed as a tab stop and from the INS+F5 dialog, this would not be a problem.

Please note that all of the above is in Chrome. 


Using the following code in the OnClientLoad event of the ComboBox:

  var _DropDown_OnClientLoad = function (sender, args) {
    var input = sender.get_inputDomElement();

    //Remove tabindex from down-arrow button. We never want to focus this button.
    $telerik.$(input).siblings("button").find("[role=button]").attr("tabindex", null);

    //hide the down-arrow button from screen readers. The entire combo box
    //should be considered a single control.
    $telerik.$(input).siblings("button").attr("aria-hidden", "true");


Won't Fix
Last Updated: 27 May 2021 09:27 by ADMIN
Using the client-side requestItems method of a RadComboBox to fire the refresh of it's items(with a call to clearCache before to ensure that the refresh is performed), doesn't always perform the async callback request, sometimes resulting in the "Loading" text being added at the top of the combo's items drop-down and staying there (as the callback to the server is never fired, so it's result never received). 

After quite a bit of trials, I finally managed to figure out that the issue arise when there is an async postback in progress on the page (to refresh an update panel) when requestItems is called.

Stepping through the requestItems call with IE F12 tools, I found that this is due to the fact that the Sys.WebForms.PageRequestManager do not perform callbacks if there is an async postback in progress. I think that the RadComboBox should detect that situation and wait until the end of the async postback to fire it's requestItems callback, otherwise the combo get stuck in the "loading in progress" state, waiting for the end of the callback that will never happens as the PageRequestManager did not start it. Additionally, in F12 Network tab, I can see that there is no request performed for the callback to request the items of the combo-box.

I reproduce the issue with the following steps:
1- Have a page with a RadComboBox, a ScriptManager with partial rendering enabled and an UpdatePanel.
2- In the browser, trigger the async postback to refresh the UpdatePanel
3- From JavaScript, while the async postback is in progress, call the requestItems method of the RadComboBox
4- Open the drop-down of the combo, and you can see the "Loading" text at the top, with the initial list of items. And it stays like this until another call is made to requestItems when there is no async post-back in progress which will actually perform the callback.
Last Updated: 08 Jan 2021 09:43 by ADMIN
Created by: Stephen
Comments: 1
Category: ComboBox
Type: Bug Report
Given a RadComboBox with search, if the user enters some search text and then clicks on one of the filtered entries in the dropdown list the validation event is fired as the entry box loses focus and results in a 'false' return from validation as it uses the 'Text' property which is the search string. Validation is then refired as a result of clicking on the entry.
However, the initial 'false' return can cause unwanted behaviour in code that depends on the validation event.
I can supply a sample project demonstrating the problem, but it needs more than the 10 MB upload limit.
Last Updated: 14 Dec 2020 15:47 by ADMIN

Hi Telerik Support,


How do I move loading box to bottom of the combo box list when using load on demand feature. the case is we're using ShowMoreResultsBox=true and EnableVirtualScrolling=true and trying to get next batch of data on a heavy query, the loading box not showing on the list see image (2020-12-03 14_31_40-Agent - Verint Express.png).

can we show the loading box on the bottom of the dropdownlist, so user is aware that the data still being loaded.

Thank you



1 2 3 4 5