Inserts group into widget. Children of widget that implement
GtkActionable can then be associated with actions in group by
setting their 'action-name' to
prefix.action-name.
If group is NULL, a previously inserted group for name is removed
from widget.
Inserts group into widget. Children of widget that implement GtkActionable can then be associated with actions in group by setting their 'action-name' to prefix.action-name. If group is NULL, a previously inserted group for name is removed from widget.