Workaround:
Set ClickToOpen = true in the control markup or if you want to set it only for the problematic browsers, use the following server-side code:

    protected void Page_Load(object sender, EventArgs e)
    {
        string userAgent = Request.UserAgent;
        string searchPattern = "ARM(?i)|Touch(?i)";

        if (System.Text.RegularExpressions.Regex.IsMatch(userAgent, searchPattern))
        {
           RadContextMenu1.ClickToOpen = true;
        }
    }

The demo for the Adaptive Behavior of the menu control (tlrk.it/1ffjNFp) is not functioning on iOS devices. It works just fine on a desktop computer, but will not respond on an iOS device. On my iOS device, when I click (touch) the menu, it fails to expand. 

However, when I download the sample code project and upgrade it to the latest version of the dll, the menu works as expected.

Currently, as mobile browsers scroll bars are transparent and initially not visible, there is no indication to suggest to users that a mobile RadMenu can be scrolled down to see items not currently displayed.
The suggestion it to add a mobile RadMenu visual indicator which shows to users that there are more items to be seen on scrolling the menu. It would enable customers to set a mobile RadMenu height that does not fit all items, and indicate to users that the expanded menu is scrollable.

I have imported the configuratorpanel.cs into my application and use it in a webform
The control works, but the compiler always creates an error in the designerfile..

it doesn't accept the namespace.
even if i comment out the namespace, then it doesn't find the configuratorpanel

<%@ Register TagPrefix="qsf"   Namespace="Telerik.QuickStart"%>
..
                        <qsf:ConfiguratorPanel runat="server" Title="neu" Expanded="false" Orientation="Horizontal" ID="cnfPanel_Folder_Neu">
                            <telerik:RadTextBox ID="tbxFolder_Title_Neu" runat="server" LabelWidth="64px" Resize="None" Skin="Silk" Width="160px" DisplayText="Neuer Order..">
                            </telerik:RadTextBox>
                            <telerik:RadTextBox ID="tbxFolder_Description_Neu" runat="server" LabelWidth="64px" Resize="None" Skin="Silk" Width="160px" DisplayText="Beschreibung..">
                            </telerik:RadTextBox>
                        </qsf:ConfiguratorPanel>

..


and in the configuratorpanel.cs file
----
namespace Telerik.QuickStart
{
    public enum ConfiguratorPanelOrientation
    {
        Horizontal,
        Vertical
    }

    public class ConfiguratorPanel : Panel, IPostBackDataHandler
    {
        protected override void RenderContents(HtmlTextWriter writer)
        {
----

If the text is too long in a RadMenuItem, when you mouse over the menu items, part of the highlighting isn't visible. The following code demonostrates. See Capture.png to see that part of the highlighting is missing. The rendering problem seems to be browser independent. I tested it using IE, Firefox, and Chrome and they all have the same problem.

<telerik:RadMenu ID="RadMenu1" runat="server" Width="100%">
    <Items>
        <telerik:RadMenuItem Text="UBorrow">
            <Items>
                <telerik:RadMenuItem Text="Borrowing Transaction Counts by Borrowing Library" NavigateUrl="~/BorrowingTransactionCountsByBorrowingLibrary.aspx" />
                <telerik:RadMenuItem Text="Borrowing Transaction Counts by Is First Lender Filled and Month"
                    NavigateUrl="~/BorrowingTransactionCountsByIsFirstLenderFilledAndMonth.aspx" />
                <telerik:RadMenuItem Text="Cancelled Lending Transaction Counts by Cancellation Reason"
                    NavigateUrl="~/CancelledLendingTransactionCountsByCancellationReason.aspx" />
                <telerik:RadMenuItem Text="Filled Borrowing Transaction Counts and Average Turnaround Times by Borrowing Library and Lending Library"
                    NavigateUrl="~/FilledBorrowingTransactionCountsAndAverageTurnaroundTimesByBorrowingLibaryAndLendingLibrary.aspx" />
                <telerik:RadMenuItem Text="Filled Borrowing Transaction Counts and Average Turnaround Times by Borrowing Library and Month"
                    NavigateUrl="~/FilledBorrowingTransactionCountsAndAverageTurnaroundTimesByBorrowingLibraryAndMonth.aspx" />
                <telerik:RadMenuItem Text="Filled Lending Transaction Counts and Average Turnaround Times by Lending Library and Borrowing Library"
                    NavigateUrl="~/FilledLendingTransactionCountsAndAverageTurnaroundTimesByLendingLibaryAndBorrowingLibrary.aspx" />
            </Items>
        </telerik:RadMenuItem>
    </Items>
</telerik:RadMenu>

_loadChildrenFromWebService() is a good client-side way of 'pre-caching' downlevel menu items while its being expanded. I would like this method to have a fully supported, external method, so that it might be maintained in future releases (it was broken in Q3 2012 for Android browsers for instance).

Additionally, it would be useful to avoid round trips, if it could work from a set of RadMenuItems, so that several RadMenuItems could have their children populated in a single request to the server.

Telerik RadMenu seems not supported in IE 10, we have telerik dll version 2010.3.1317.20
We have submenus which are not getting open when hover over the menus. Even main menus not getting open automatically when hover, 
it needs to keep on moving the cursor on the menu, then only it gets open automatically. This issue occure only in IE 10. 
It works correctly on all the other versions of browser.
Here is a link to replicate the issue when open in IE 10
http://www.exair.com
On the top nav menu bar, go to "Buy Now" menu, it has other sun menus, which are not open at all.
Please let me know how do I resolve this issue.

Research the ability to have the RadMenu behave responsively.

(On a related thread, there is a wider-oriented customer request for a responsive framework)

Version 417 - Menu works like a charm, animation goes from top to bottom (on hover) normally; 

Version 611 upgrade - Menu breaks, Animation starts from bottom to top. (on hover) This is unexpected and breaks prior application functionality; We've tried replacing the binaries from 417 to 611 and back again to confirm this.

In the latest version of the controls (v.2012.3.1205.40 Dev) RadMenu links are not clickable on iPad/iPhone iOS 5.1 or iOS 6.