The want to use the footer tile at the end
to fill leftover space at the bottome right.
So lets assert that we actually dealing with
a footer tile, just in case something changes
in the future that might have us end up with
some other kind of tile.
{
GtkListTile *filler;
tile = gtk_list_item_manager_get_last (self->item_manager);
+ g_assert (gtk_list_tile_is_footer (tile));
filler = gtk_list_tile_append_filler (self->item_manager, tile);
gtk_list_tile_set_area_position (self->item_manager,
filler,