Makes all newly-created widgets as composite children until
the corresponding Widget.popCompositeChild call.
A composite child is a child that’s an implementation detail of the
container it’s inside and should not be visible to people using the
container. Composite children aren’t treated differently by GTK+ (but
see Container.foreach vs. Container.forall), but e.g. GUI
builders might want to treat them in a different way.
Deprecated: This API never really worked well and was mostly unused, now
we have a more complete mechanism for composite children, see Widget.classSetTemplate.
Makes all newly-created widgets as composite children until the corresponding Widget.popCompositeChild call.
A composite child is a child that’s an implementation detail of the container it’s inside and should not be visible to people using the container. Composite children aren’t treated differently by GTK+ (but see Container.foreach vs. Container.forall), but e.g. GUI builders might want to treat them in a different way.