Yep that is what I was looking for thanks
So need to use
RadDropDownButton not RadExpander
<telerik:RadDropDownButton Height="20" Width="100" DropDownPlacement="Top">
<telerik:RadDropDownButton.DropDownContent>
<Label>Drop Content</Label>
</telerik:RadDropDownButton.DropDownContent>
</telerik:RadDropDownButton>