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.
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.