<@U68L6T95E> I think this example meets your requ...
# tornadofx
@dr.fornax I think this example meets your requirements. I also pulled out "Phone" into a promptText rather than an actual value. Your problem was related to the terms of the editable flag. When you bound model.label and then called isEditable=true, you wiped out the model.label value with an empty value coming from the ComboBox (see the Javadocs). So, if you defer the binding, the value will be retained post-editable and the binding will work as you expect.