Treeview sortingis this a bug

[Mike Martin <redtux1 gmail com>]

I am trying to toggle sorting on a liststore, so I am trying to use

$list->get_column(0)->set_sort_column_id(-2)

where list is a treeview containing a liststore

as per

GTK_TREE_SORTABLE_UNSORTED_SORT_COLUMN_ID

#define GTK_TREE_SORTABLE_UNSORTED_SORT_COLUMN_ID (-2)

The GTK_TREE_SORTABLE_DEFAULT_SORT_COLUMN_ID can be used to make a GtkTreeSortable use no sorting.

referenced on https://developer.gnome.org/gtk3/stable/GtkTreeSortable.html#GTK-TREE-SORTABLE-UNSORTED-SORT-COLUMN-ID:CAPS

However I get the error message

gtk_tree_view_column_set_sort_column_id: assertion 'sort_column_id >= -1' failed

thanks

Mike