GtkStyle for a widget (widget->style). You probably don't
want to use this function; it interacts badly with themes, because
themes work by replacing the GtkStyle. Instead, use
gtkWidgetModifyStyle.gtkWidgetSetStyle(object, style = NULL)objectstyleGtkStyle, or NULL to remove the effect of a previous
gtkWidgetSetStyle and go back to the default style. [ allow-none ]