gtk.types.SensitivityType.On if the dropdown button is sensitive when the model is empty, gtk.types.SensitivityType.Off if the button is always insensitive or gtk.types.SensitivityType.Auto if it is only sensitive as long as the model has one item to be selected.
Deprecated: Use gtk.drop_down.DropDown
Returns whether the combo box sets the dropdown button sensitive or not when there are no items in the model.