I'm used to using the .NET rad combobox in web forms which might be why I'm confused by the silverlight version. I would like my combox to have autocomplete functionality, but to NOT select the first match. I think in the web forms version there was a property called "markFirstMatch" which I could set to false. The problem is that I have RIA domainsources which are binding to the selected item in the rad combobox and when a user types the first letter it finds the first match and then automatically updates the RIA domainsource. I don't really want that to happen until the user has definitively selected an item in the combobox. Is there a way to do this in the silverlight rad combobox?