void gtk_tree_view_set_expander_column ( GtkTreeView* tree_view, GtkTreeViewColumn* column )
Sets the column to draw the expander arrow at. It must be in
NULL, then the expander arrow is always at the first
If you do not want expander arrow to appear in your tree, set the expander column to a hidden column.
NULL, or the column to draw the expander arrow at.
The argument can be
The data is owned by the caller of the method.