Currently when a combo box is used on an edit form, when the combo box first loads, the value property it is bound to (e.g. an int id) is displayed as the text until the databound event fires, and the text value associated with that value can be loaded.  It gives the combo boxes an unprofessional look, as they briefly display a number until they are done loading.  It also creates some other problems when you have a custom filter function, as described here:

http://www.telerik.com/account/support-tickets/view-ticket.aspx?threadid=781390

I recognize that you would not want to change the default behavior since it would be a breaking change, but could you add a flag to toggle this behavior off.  You could add a property called "DefaultTextToValue" which is set to True by default, and if you set to false, the display would remain blank until the text value was set by the databound event.