Listbox displayed incorrectly

[Rodney]

I'm having a very intermittent problem with two list boxes with "allow transfer" enabled. The first time the page loads, sometimes, the left side list box with all the selectable items overflows the bottom of the container and the right one gets an extra line before the title and before the list items. If I move an item in either direction the page corrects itself and displays correctly. Then after that, I can log out of the app, open it in a new browser window and no problems. But the first time in, particularly after recycling IIS I have this problem. See attached screenshots and HTML below. The postback is for sorting.

Thanks

Rodney

<asp:UpdatePanel runat="server" ID="updPnlRoles">
    <ContentTemplate>
        <telerik:RadListBox runat="server" ID="rlbxAvailableRoles" Height="210" Width="230" AllowTransfer="true" TransferToID="rlbxSelectedRoles"
            ButtonSettings-AreaWidth="35px"
            ButtonSettings-ShowTransferAll="false" AllowTransferOnDoubleClick="true" SelectionMode="Multiple" EnableDragAndDrop="true"
            AutoPostBackOnTransfer="true">
            <HeaderTemplate>
                <h3>Available Roles</h3>
            </HeaderTemplate>
        </telerik:RadListBox>
        <telerik:RadListBox runat="server" ID="rlbxSelectedRoles" Height="210" Width="190" EmptyMessage="Select at least one role"
            AllowTransferOnDoubleClick="true" SelectionMode="Multiple" EnableDragAndDrop="true" AutoPostBackOnTransfer="true">
            <HeaderTemplate>
                <h3>Selected Roles</h3>
            </HeaderTemplate>
        </telerik:RadListBox>
        <asp:CustomValidator ID="cvSelectedRoles" runat="server" ErrorMessage="You must have at least 1 role"
            ClientValidationFunction="cvSelectedRoleVal" ControlToValidate="rlbxSelectedRoles" ValidateEmptyText="true"
            CssClass="validator" ValidationGroup="userValidations">
        </asp:CustomValidator>
    </ContentTemplate>
</asp:UpdatePanel>

[Nencho]

Hello Rodney,

I am afraid that we are not familiar with such a problem related with the RadListBox. which is why we would need to replicate it, so we could try to pin down the reason for it. Unfortunately, after different tests, using the provided code-snippet, the problem was not replicated on our side.

Since such problem might be caused by side factors, e.g environment where the control is implemented and so on, I would like to ask you to provide us with an isolate sample, where the problem does resides after the mentioned iis reset. 

Also, could you specify whether you have observed such visual defects with our controls on your page? In addition, do you experience any js errors on your page?

I am looking forward to your reply.

Regards,
Nencho
Telerik by Progress