If I have for example three values in my combo, a, b and c and the user starts typing x (a letter that does not match existent items) nothing is selected as expected. But when you want to check the list and click the dropdown, the list is empty on the first click. The user has to click again to see the list populated. It should be ok on the first click...

Using Silverlight4, WCF RIA Services, Infragistics 2010.3