'Process changes in the header_note_source_field combo box'

def header_note_source_field_changed(self, new_index):

    new_source = self.header_note_source_field.currentText()
    self.header_note_source_field_name = new_source
    if (new_source > ''):
        header_note_source_spec = self.header_note_source_fields[unicode(new_source)]
        self.header_note_source_field_name = header_note_source_spec['field']
