RadComboBox EmptyMessage not showing on initial load

Question

For some reason my RadComboBox "EmptyMessage" is not showing on the initial load of the page but it does after I focus and blur out of the control. How can I force my "EmptyMessage" to show by default?

My .aspx is as follows:

<telerik:RadComboBox 
  ID="SomeFilter" runat="server"
  EmptyMessage="Choose..."
  OnClientSelectedIndexChanging="OnClientSelectedIndexChanging"
  OnClientDropDownOpening="OnClientDropDownOpening"
  OnClientDropDownClosing="OnClientDropDownClosing"
  OnClientBlur="OnClientBlur">
    <ItemTemplate>
      <asp:CheckBox ID="ItemSelector" runat="server"  /> 
      <asp:Label runat="server" ID="ItemLabel" AssociatedControlID="ItemSelector">
        <%# DataBinder.Eval(Container, "Text") %>
      </asp:Label>
    </ItemTemplate>
</telerik:RadComboBox>

My code behind:

protected void Page_Load(object sender, EventArgs e)
{
  if (!Page.IsPostBack)
  {
    SetSomeFilterDropDown();
  }
}

private void SetSomeFilterDropDown()
{
  SomeFilter.Items.Add(new RadComboBoxItem("Test1", "Test1"));
  SomeFilter.Items.Add(new RadComboBoxItem("Test2", "Test2"));
  SomeFilter.Items.Add(new RadComboBoxItem("Test3", "Test3"));
  SomeFilter.DataBind();
}

I also have the following javascript methods in my .aspx:

var supressDropDownClosing = false;

    OnClientDropDownClosing = function (sender, eventArgs) {
        eventArgs.set_cancel(supressDropDownClosing);
        sender.clearSelection();
    }

    OnClientSelectedIndexChanging = function (sender, eventArgs) {
        eventArgs.set_cancel(supressDropDownClosing);
    }

    OnClientDropDownOpening = function (sender, eventArgs) {
        supressDropDownClosing = true;
    }

    OnClientBlur = function (sender) {
        supressDropDownClosing = false;
        sender.toggleDropDown();
    }

My combobox defaults to "Test1" by default instead of "Choose...". Once I open and close the combobox, however, the default changes to "Choose...".

Answer 1

Since this RadComboBox is not loading on demand, in order for the EmptyTextMessage to work as you expect, You need to also set the property AllowCustomText to True

From Telerik:

The EmptyMessage property can be used when the AllowCustomText property is set to True (it is always true in a Load-on-Demand scenario). It sets a text in the input field of the combobox. This text disappears when the combobox gets the focus and appears again on blur if no item is selected.