Gets the set containing all currently selected items in the model.
This function may be slow, so if you are only interested in single item,
consider using [method@Gtk.SelectionModel.is_selected] or if you are only
interested in a few, consider [method@Gtk.SelectionModel.get_selection_in_range].
Gets the set containing all currently selected items in the model.
This function may be slow, so if you are only interested in single item, consider using [method@Gtk.SelectionModel.is_selected] or if you are only interested in a few, consider [method@Gtk.SelectionModel.get_selection_in_range].