The DojoComboBox widget defines a presentation that includes a visible value, which represents the current selection, and a dropdown list of values. This widget is based on the Dojo dijit.form.ComboBox definition.
When the Dojo combo box is the view component of a controller, the value that the view receives from the model component of the controller can take precedence over the value that you assign to the value property of the combo box. For details on controllers, see “Rich UI validation and formatting.”
If you assign to the value property a value that is not in the array, the assigned value will be visible; but if the user selects a value from the dropdown list, the assigned value is no longer available.