Empty message for combobox with check items

[Phasu]

It seems empty message for ComboBox with check items does not work.

Even though I have added a property of EmptyMessage="Select", my still shows nothing instead of Select.

How can I make default message show up when no item is selected?

Here is my code

<telerik:RadComboBox SkinId="ComboboxWithCheckbox" runat="server" EnableTextSelection="true" OnClientDropDownClosing="OnClientClosing" OnClientLoad="OnClientClosing"
    CheckedItemsTexts="DisplayAllInInput" AllowCustomText="true"  filter="Contains"  CheckBoxes="true"
    EnableCheckAllItemsCheckBox="false" CheckedItems="true" DropDownAutoWidth="Disabled">
    <Localization CheckAllString="All" AllItemsCheckedString="All" ItemsCheckedString="Items Selected" />
</telerik:RadComboBox>

Here is my code

<telerik:RadComboBox ID="cbModel" runat="server" Width="100%"
       DataTextField="Model" DataValueField="Model" EmptyMessage="Select"
       ResolvedRenderMode="Classic" skinid="ComboboxWithCheckbox"
       DataSourceID="ModelDataSource"  >
</telerik:RadComboBox>