notebook, notebooks sharing
the same group identificator will be able to exchange tabs
via drag and drop. A notebook with group identificator -1 will
not be able to exchange tabs with any other notebook.
WARNING: gtk_notebook_set_group_id has been deprecated since version 2.12 and should not be used in newly-written code. use gtkNotebookSetGroup instead.
gtkNotebookSetGroupId(object, group.id)objectgroup.id