GtkContaineradd

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_pack_start() and gtk_grid_attach() as an alternative to gtk_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.