Bug: ComboBoxFilteringBehavior incorrectly selects first item in list when there is no match

[Aleksandar]

My FindFullMatchIndex method returns -1 when an item is not found. Instead of selecting no items and leaving the scroll position where it's at like the default search text behavior; the combobox scrolls the list to the top and selects the first item in the list. How can I prevent the combobox from selecting the first item in the list when there isn't a match?

[Nasko]

Hello Aleksandar,

The observed by you behavior is an expected one with the current implementation of RadComboBox. When the FindFullMatchIndex returns -1 the first item is expected to be highlighted and currently this is how the control is expected to work and there isn't any approach to use in order  to modify or alter that behavior. Some more information concerning the FindFullMatchIndex and how it behaves you could find on the following link from our documentation:
http://docs.telerik.com/devtools/wpf/controls/radcombobox/features/filteringbehavior

We hope the provided information will be helpful for you.

Regards,
Nasko
Telerik by Progress