def insert_application_key_label(index, display_code, text)
      @repaint_required = true
      labels = key_labels()
      labels.insert(index, [display_code , text] )
    end
def insert_application_key_label(index, display_code, text)
      @repaint_required = true
      labels = key_labels()
      labels.insert(index, [display_code , text] )
    end
inserts an application label at given index
 to add the key, use create_datakeys to add bindings
 remember to call restore_application_key_labels after updating/inserting