Issue 1 - Items in ListBox missing and/or cut off.
Issue 2 - Incorrect highlighting
Issue 3 - Moving items sometimes doesn't work
Issue 4 - Scrolling of items scrolls the whole page instead (sometimes)
Issue 5 - Bottom ListBox cut off (Chrome dev tools, iPhone 5/SE)
Issue 6 - Scrolling in ListBox sometimes selects items
Issue 7 - Sometimes items in the Listboxes cannot be selected at all. (Intermittent)

I have a few instances where I need OnClientSelectedIndexChanging inorder to stop the listbox selectedIndexChanged event from posting back in certain cases. In those cases I stop it from posting back by setting the e.set_cancel(true);

function CheckForListBoxReorder_OnClientEvent(sender, e) {
    if (ListboxReordered()) {
        alert('Please save changes to the bus order.');
        e.set_cancel(true);
    }
}

This works very nicely, but I'm getting many errors because although it looks like it's still selected to the proper row in the listbox the selectedIndex is now -1.

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>

The error is observed when an item that is added from the client-side is to be transferred to other RadListBox from a RadListBox that is loading on demand. Unfortunately the control supports such scenario only when that transfer is made from the server side.

When there are few checkbox items in RadListBox (i.e. there is no scroll bar), checked items cannot be unchecked. The issue is reproducible in iPAD.