RadComboBox should work in such scenarios, I guess that there is a problem with the bindings that are applied on the control. For example, looking at your code snippets, I guess that there is something strange - RadComboBox ItemsSource is bound to a property called Default.Theme, which I guess is some kind of collection; the SelectedItem property is also bound to Default.Theme - I suppose you should be binding to something else, if this property is the same as the ItemsSource's source. A simple application that could be used to observe the problem would be of great help, so I would like to kindly ask you to create one and send it to us through a new support ticket.
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