When combo popups to the top of the page it goes out of the browser viewport.
Reproduce: 
A RadComboBox on the bottom of your page and the page height is larger than the viewport.
When you scroll down the page to the RadComboBox and open it the itembox (100+ items) height will be higher than the view port.
See attachment 'RadComboBox.png'

Also the auto shrink doesn’t work in this situation see attachment RadComboBox2.png

Selecting an item from the RadComboBox and then pressing Enter key, does not trigger the default button(if set) of the form/panel in IE and Chrome. The workaround is to handle the client-side OnClientKeyPressing event of the RadComboBox and manually trigger the clicking of the default button.For example:

ASPX:

    <asp:Panel ID="Panel1" runat="server" DefaultButton="RadButton1">
        <telerik:RadTextBox ID="RadTextBox1" runat="server">
        </telerik:RadTextBox>
        <asp:Label ID="Label1" Text="" runat="server" />
        <telerik:RadButton ID="RadButton1" runat="server" OnClick="OnClick1" Text="Click" />
        <telerik:RadComboBox ID="RadComboBox1" runat="server" OnClientKeyPressing="OnClientKeyPressing">
            <Items>
                <telerik:RadComboBoxItem Text="text1" Value="val1" />
                <telerik:RadComboBoxItem Text="text2" Value="val2" />
                <telerik:RadComboBoxItem Text="text3" Value="val3" />
            </Items>
        </telerik:RadComboBox>
    </asp:Panel>

JavaScript:
    <telerik:RadCodeBlock ID="RadCodeBlock1" runat="server">
        <script type="text/javascript">
            function OnClientKeyPressing(sender, args) {

                if (args.get_domEvent().keyCode == 13) {
                    $find("<%=RadButton1.ClientID %>").click();
                }
            }
        </script>
    </telerik:RadCodeBlock>

Using the .get_value() in the OnClientDropDownClosed event of RadComboBox, produces empty value. The OnClientSelectedIndexChanged event works fine, but I need to be able to kick off the javascript even if the selected index doesn't change. 

My RadComboBox element:

<telerik:RadComboBox ID="CustomerSearch" runat="server" Width="180" Height="160"  
        MarkFirstMatch="true"  AllowCustomText="true" CssClass="CustomerSearch" AutoPostBack="false" 
        EnableLoadOnDemand="true" EnableVirtualScrolling="true" OnItemsRequested="CustomerSearch_ItemsRequested" 
        OnClientDropDownClosed="searchnav" EmptyMessage="Select a customer" DataSourceID="dsCustomer" DataTextField="CustomerName" 
        DataValueField="NavPath" BackColor="White" Skin="Forest" />

My SQLDataSource element:
<asp:SqlDataSource ID="dsCustomer" runat="server"
    SelectCommand="CustomerSearchName" SelectCommandType="StoredProcedure">
</asp:SqlDataSource>

My Javascript:
<telerik:RadScriptBlock ID="RadScriptBlock1" runat="server">
    <script type="text/javascript">
        function searchnav(sender, args) {
            var iframe = document.getElementById('ctl00_iMainPages');
            iframe.src = sender.get_value();
        }
    </script>
</telerik:RadScriptBlock>

In the meantime you can use the following css workaround that will fix the issue: 

.rcbAutoWidthResizer .rcbScroll {
	overflow: visible !important;
}
 
/*To target IE 6, 7 and 8*/
@media \0screen\,screen\9 {
	.rcbAutoWidthResizer .rcbScroll {
		overflow: auto !important;
	}
}
 
/*To target IE 9 and 10*/
@media screen and (min-width:0\0) {
	.rcbAutoWidthResizer .rcbScroll {
		overflow: auto !important;
	}
}

We have evaluated your controls for few days for the last 3 years now. And you still dont support check boxes and load on demand. (we keep getting the same response from your forms). There are other companies already do that. If you can include this feature in your future development that will be great. As i have mentioned to your sales team about the team size and the number of license we need but unfortunately this feature is not available so we can not buy your controls. Thanks

Hi,
RadComboBox does not having direct way to set its height, not dropdown height.
It is required functionality because its height should be as per website design.

If we dynamically remove highlighted item from a ComboBox at clientside, afterwards get_highlightedItem still returns that deleted item.
ComboBox takes care of deleting selected item at like 497 of RadComboBox.js. Highlighted item should be taken care of too.

This feedback item has been raised from this forum thread: http://www.telerik.com/community/forums/aspnet-ajax/combobox/enablecheckallitemscheckbox-all-entry-doesnt-fire-onitemchecked-event.aspx

This issue was first raised back in Sep '11 as it was suggested that 'it was in the plan for a future release'.

I've added this item here in the feedback portal to ensure that it's not got lost

Hello,

I have a resize problem for Radcombobox .I can't change the height of default textbox of combobox.

Could you please help me?

Based on customer feedback:

In certain cases, the client side autowidth does not perform well enough or the results are not exactly what one would expect.

Instead, server side autowidth could do the job. True, there are drawbacks to this approach, like font name and font size, but it could be configurable.

We are using the combo box drop down:

                <telerik:RadComboBox ID="rcbAccounts" runat="server" Width="360" DropDownWidth="810" OffsetX="-200"
                    DataValueField="AcctNumber" DataTextField="DisplayString" AutoPostBack="True"
                    AllowCustomText="True" Filter="Contains" ExpandDelay="0" CollapseDelay="0" MaxHeight="300"
                    OnClientDropDownOpening="OnRcbAccountsOpening" Skin="CustomTelerikSkin" EnableEmbeddedSkins="false"
                    EnableViewState="false" EnableScreenBoundaryDetection="true" >
                    <HeaderTemplate>
                        <ul>
                            <li class="rcbColumn" style="width: 330px">Name</li>
                            <li class="rcbColumn" style="width: 70px">Acct #</li>
                            <li class="rcbColumn" style="width: 90px">Type</li>
                            <li class="rcbColumn" style="width: 150px">Address</li>
                            <li class="rcbColumn" style="width: 110px">City</li>
                        </ul>
                    </HeaderTemplate>
                    <ItemTemplate>
                        <ul>
                            <li class="rcbColumn" style="width: 330px">
                                <%#DataBinder.Eval(Container.DataItem, EC.ACCT_NAME).ToString()%></li>
                            <li class="rcbColumn" style="width: 70px">
                                <%#DataBinder.Eval(Container.DataItem, EC.ACCT_NO).ToString()%></li>
                            <li class="rcbColumn" style="width: 90px">
                                <%#DataBinder.Eval(Container.DataItem, EC.ACCT_TYPE).ToString()%></li>
                            <li class="rcbColumn" style="width: 150px">
                                <%#DataBinder.Eval(Container.DataItem, EC.ACCT_ADDR1).ToString()%></li>
                            <li class="rcbColumn" style="width: 110px">
                                <%#DataBinder.Eval(Container.DataItem, EC.ACCT_CITY).ToString()%></li>
                        </ul>
                    </ItemTemplate>
                </telerik:RadComboBox>

It looks like the attached at runtime.  My question is:  Can we align the dropdown area to be left-aligned with the control?  In some cases, the left part of the data gets cut off by the browser window.

RadComboBox will open up in case that ScreenBoundaryDetection is enabled and there is not enough space below even if the space above is much less than below.
Like in a vertically narrow frame with the ComboBox being at the top of the page. 
It seems better to compare the space below with above and put it where there is more space.

There is no RTL boundary detection in ComboBox, e.g. no _elementOverflowsLeftScreenBorder in RadComboBox.DropDown.js

rad combobox on clientblur event setting custom text fine when we are going to press tab  key but we are getting issue when we are selecting item from rad combo box manually using mouse.on clicking suppose i have text :  ils - apple  i have called onclien

Hi There,
i am working on asp.net 4.0 with telerik asp.net ajax control. The problem i am facing is that all the controls are not working but the same files were working in asp.net 3.5, for example i am attaching a error page which is showing a radcombobox as a text box. I am not being able to figure out the issue/bug whether it is because of RadStyleSheetManager or RadScriptManager.

Kindly help me with this issue.

There is problem selected value radcombox with Ajax modal pop up pls suggest the solution for that

When RadCombobox is inside fixed div element and is expanded it doesn't scroll as expected. The dropdown container should stay fixed as the combo's input element.