Sets label_widget as the widget that will be used as the label
for button. If label_widget is NULL the label property is used
as label. If label is also NULL, the label in the stock item
determined by the stock-id property is used as label. If
stock-id is also NULL, button does not have a label.
Sets label_widget as the widget that will be used as the label for button. If label_widget is NULL the label property is used as label. If label is also NULL, the label in the stock item determined by the stock-id property is used as label. If stock-id is also NULL, button does not have a label.