Container.add

Adds widget to container. Typically used for simple containers such as #GtkWindow, #GtkFrame, or #GtkButton; for more complicated layout containers such as #GtkBox or #GtkGrid, this function will pick default packing parameters that may not be correct. So consider functions such as [gtk.box.Box.packStart] and [gtk.grid.Grid.attach] as an alternative to [gtk.container.Container.add] in those cases. A widget may be added to only one container at a time; you can’t place the same widget inside two different containers.

Note that some containers, such as #GtkScrolledWindow or #GtkListBox, may add intermediate children between the added widget and the container.